docs: use proper emdashes instead of double hyphens: "--" => "\(em"

Also, remove redundant double quotes, protect single quotes from
possibly getting misinterpreted, and protect periods from getting
treated as end-of-sentence.  Also, use \e instead of \\.

(Overlong lines are left alone -- they don't bother me.)

This partially addresses https://bugs.debian.org/1095957.
Reported-by: Bjarni Ingi Gislason <bjarniig@simnet.is>

doc/nano.1

@@ -101,7 +101,7 @@ A literal control code (except \fB^J\fR) can be inserted by typing
 .sp
 The two lines at the bottom of the screen show some important commands;
 the built-in help (\fB^G\fR) lists all the available ones.
-The default key bindings can be changed via a \fInanorc\fR file -- see
+The default key bindings can be changed via a \fInanorc\fR file \(em see
 .BR nanorc (5).
 
 .\" Never hyphenate these:
@@ -120,8 +120,8 @@ When saving a file, back up the previous version of it, using the current
 filename suffixed with a tilde (\fB~\fR).
 .TP
 .BI \-C " directory\fR, " \-\-backupdir= directory
-Make and keep not just one backup file, but make and keep a uniquely
-numbered one every time a file is saved -- when backups are enabled (\fB\-B\fR).
+Make and keep not just one backup file, but make and keep a uniquely numbered
+one every time a file is saved \(em when backups are enabled (\fB\-B\fR).
 The uniquely numbered files are stored in the specified \fIdirectory\fR.
 .TP
 .BR \-D ", " \-\-boldtext
@@ -132,7 +132,7 @@ This can be overridden for specific elements by setting the options
 nanorc file.  See \fBnanorc\fR(5).
 .TP
 .BR \-E ", " \-\-tabstospaces
-Convert each typed tab to spaces -- to the number of spaces
+Convert each typed tab to spaces \(em to the number of spaces
 that a tab at that position would take up.
 (Note: pasted tabs are not converted.)
 .TP
@@ -195,7 +195,7 @@ don't allow suspending; don't allow spell checking;
 don't allow a file to be appended to, prepended to, or saved under a
 different name if it already has one; and don't make backup files.
 Restricted mode can also be activated by invoking \fBnano\fR
-with any name beginning with 'r' (e.g. "rnano").
+with any name beginning with 'r' (e.g.\& "rnano").
 .TP
 .BR \-S ", " \-\-softwrap
 Display over multiple screen rows lines that exceed the screen's width.
@@ -338,7 +338,7 @@ unless \fB\-\-restricted\fR is given too.
 .BR \-w ", " \-\-nowrap
 Do not automatically hard-wrap the current line when it becomes overlong.
 This is the default.  (This option is the opposite of \fB\-b\fR
-(\fB\-\-breaklonglines\fR) -- the last one given takes effect.)
+(\fB\-\-breaklonglines\fR) \(em the last one given takes effect.)
 .TP
 .BR \-x ", " \-\-nohelp
 Don't show the two help lines at the bottom of the screen.
@@ -459,7 +459,7 @@ the current filename in order to make it unique.  In multibuffer mode,
 \fBnano\fR writes all open buffers to their respective emergency files.
 .sp
 If you have any question about how to use \fBnano\fR in some specific
-situation, you can ask on \fIhelp-nano@gnu.org\fR.
+situation, you can ask on \fIhelp\-nano@gnu.org\fR.
 
 .SH BUGS
 The recording and playback of keyboard macros works correctly only on a

doc/nanorc.5

@@ -56,7 +56,7 @@ lines at the end of your \fInanorc\fR file:
 The configuration file accepts a series of \fBset\fR and \fBunset\fR
 commands, which can be used to configure nano on startup without using
 command-line options.  Additionally, there are some commands to define
-syntax highlighting and to rebind keys -- see the two separate sections
+syntax highlighting and to rebind keys \(em see the two separate sections
 on those.  \fBnano\fR reads one command per line.
 All commands and keywords should be written in lowercase.
 .sp
@@ -93,9 +93,9 @@ line is the beginning of a paragraph).
 When saving a file, create a backup file by adding a tilde (\fB~\fR) to
 the file's name.
 .TP
-.B set backupdir "\fIdirectory\fR"
+.B set backupdir \fIdirectory\fR
 Make and keep not just one backup file, but make and keep a uniquely
-numbered one every time a file is saved -- when backups are enabled
+numbered one every time a file is saved \(em when backups are enabled
 with \fBset backup\fR or \fB\-\-backup\fR or \fB\-B\fR.
 The uniquely numbered files are stored in the specified \fIdirectory\fR.
 .TP
@@ -249,7 +249,7 @@ When needed, use \fBunset breaklonglines\fR instead.
 Use this color combination for line numbers.
 See \fBset titlecolor\fR for more details.
 .TP
-.B set operatingdir "\fIdirectory\fR"
+.B set operatingdir \fIdirectory\fR
 \fBnano\fR only reads and writes files inside \fIdirectory\fR and its
 subdirectories.  Also, the current directory is changed to here, so
 files are inserted from this directory.  By default, the operating
@@ -283,8 +283,8 @@ When option \fBminibar\fR or \fBzero\fR is in effect,
 .TP
 .BI "set quotestr """ regex """
 Set the regular expression for matching the quoting part of a line.
-The default value is "\fB^([\ \\t]*([!#%:;>|}]|//))+\fR".
-(Note that \fB\\t\fR stands for an actual Tab character.)
+The default value is "\fB^([\ \et]*([!#%:;>|}]|//))+\fR".
+(Note that \fB\et\fR stands for an actual Tab character.)
 This makes it possible to rejustify blocks of quoted text when composing
 email, and to rewrap blocks of line comments when writing source code.
 .TP
@@ -362,14 +362,14 @@ Use a tab size of \fInumber\fR columns.  The value of \fInumber\fR must be
 greater than 0.  The default value is \fB8\fR.
 .TP
 .B set tabstospaces
-Convert each typed tab to spaces -- to the number of spaces
+Convert each typed tab to spaces \(em to the number of spaces
 that a tab at that position would take up.
 (Note: pasted tabs are not converted.)
 .TP
 .B set titlecolor \fR[\fBbold,\fR][\fBitalic,\fR]\fIfgcolor\fB,\fIbgcolor\fR
 Use this color combination for the title bar.
 Valid names for the foreground and background colors are:
-.BR red ", " green ", " blue ", " magenta ", " yellow ", " cyan ", "
+.BR red ", " green ", " blue ", " magenta ", " yellow ", " cyan ,
 .BR white ", and " black .
 Each of these eight names may be prefixed with the word \fBlight\fR
 to get a brighter version of that color.
@@ -379,12 +379,12 @@ On a Linux console, \fBlight\fR does not have
 any effect for a background color.
 On terminal emulators that can do at least 256 colors,
 other valid (but unprefixable) color names are:
-.BR pink ", " purple ", " mauve ", " lagoon ", " mint ", "
-.BR lime ", " peach ", " orange ", " latte ", "
-.BR rosy ", " beet ", " plum ", " sea ", " sky ", " slate ", "
-.BR teal ", " sage ", " brown ", " ocher ", " sand ", " tawny ", "
+.BR pink ", " purple ", " mauve ", " lagoon ", " mint ,
+.BR lime ", " peach ", " orange ", " latte ,
+.BR rosy ", " beet ", " plum ", " sea ", " sky ", " slate ,
+.BR teal ", " sage ", " brown ", " ocher ", " sand ", " tawny ,
 .BR brick ", " crimson ", and " normal
--- where \fBnormal\fR means the default foreground or background color.
+\(em where \fBnormal\fR means the default foreground or background color.
 On such emulators, the color may also be specified as a three-digit hexadecimal
 number prefixed with \fB#\fR, with the digits representing the amounts of red,
 green, and blue, respectively.  This tells \fBnano\fR to select from the
@@ -446,8 +446,8 @@ The period \fB.\fR matches any single character,
 \fB*\fR means the preceding item may be matched zero or more times,
 \fB+\fR means the preceding item must be matched one or more times,
 \fB^\fR matches the beginning of a line, and \fB$\fR the end,
-\fB\\<\fR matches the start of a word, and \fB\\>\fR the end,
-and \fB\\s\fR matches a blank.
+\fB\e<\fR matches the start of a word, and \fB\e>\fR the end,
+and \fB\es\fR matches a blank.
 It also means that lookahead and lookbehind are not possible.
 A complete explanation can be found in the manual page of GNU grep:
 \fBman grep\fR.
@@ -520,7 +520,7 @@ This overrides the setting of the \fBtabstospaces\fR option.
 Paint all pieces of text that match the extended regular expression
 \fIregex\fR with the given foreground and background colors, at least
 one of which must be specified.  Valid color names are:
-.BR red ", " green ", " blue ", " magenta ", " yellow ", " cyan ", "
+.BR red ", " green ", " blue ", " magenta ", " yellow ", " cyan ,
 .BR white ", and " black .
 Each of these eight names may be prefixed with the word \fBlight\fR
 to get a brighter version of that color.
@@ -530,12 +530,12 @@ On a Linux console, \fBlight\fR does not have
 any effect for a background color.
 On terminal emulators that can do at least 256 colors,
 other valid (but unprefixable) color names are:
-.BR pink ", " purple ", " mauve ", " lagoon ", " mint ", "
-.BR lime ", " peach ", " orange ", " latte ", "
-.BR rosy ", " beet ", " plum ", " sea ", " sky ", " slate ", "
-.BR teal ", " sage ", " brown ", " ocher ", " sand ", " tawny ", "
+.BR pink ", " purple ", " mauve ", " lagoon ", " mint ,
+.BR lime ", " peach ", " orange ", " latte ,
+.BR rosy ", " beet ", " plum ", " sea ", " sky ", " slate ,
+.BR teal ", " sage ", " brown ", " ocher ", " sand ", " tawny ,
 .BR brick ", " crimson ", and " normal
--- where \fBnormal\fR means the default foreground or background color.
+\(em where \fBnormal\fR means the default foreground or background color.
 On such emulators, the color may also be specified as a three-digit hexadecimal
 number prefixed with \fB#\fR, with the digits representing the amounts of red,
 green, and blue, respectively.  This tells \fBnano\fR to select from the
@@ -573,7 +573,7 @@ Extend the syntax previously defined as \fIname\fR with another
 \fIcommand\fR.  This allows adding a new \fBcolor\fR, \fBicolor\fR,
 \fBheader\fR, \fBmagic\fR, \fBformatter\fR, \fBlinter\fR, \fBcomment\fR,
 or \fBtabgives\fR
-command to an already defined syntax -- useful when you want to
+command to an already defined syntax \(em useful when you want to
 slightly improve a syntax defined in one of the system-installed
 files (which normally are not writable).
 
@@ -612,7 +612,7 @@ The format of \fIkey\fR should be one of:
 .TP 7
 .BI ^ X
 where \fIX\fR is a Latin letter, or one of several ASCII characters
-(@, ], \\, ^, _), or the word "Space".
+(@, ], \e, ^, _), or the word "Space".
 Example: ^C.
 .TP
 .BI M\- X
@@ -666,11 +666,11 @@ Inserts a file into the current buffer (at the current cursor position),
 or into a new buffer when option \fBmultibuffer\fR is set.
 .TP
 .B whereis
-Starts a forward search for text in the current buffer -- or for filenames
+Starts a forward search for text in the current buffer \(em or for filenames
 matching a string in the current list in the file browser.
 .TP
 .B wherewas
-Starts a backward search for text in the current buffer -- or for filenames
+Starts a backward search for text in the current buffer \(em or for filenames
 matching a string in the current list in the file browser.
 .TP
 .B findprevious
@@ -847,7 +847,7 @@ Goes to a specific line (and column if specified).  Negative numbers count
 from the end of the file (and end of the line).
 .TP
 .B findbracket
-Moves the cursor to the bracket (or brace or parenthesis, etc.) that matches
+Moves the cursor to the bracket (or brace or parenthesis, etc.\&) that matches
 (pairs) with the one under the cursor.  See \fBset matchbrackets\fR.
 .TP
 .B anchor
@@ -883,7 +883,7 @@ Deletes the character under the cursor.
 Deletes the character before the cursor.
 .TP
 .B recordmacro
-Starts the recording of keystrokes -- the keystrokes are stored
+Starts the recording of keystrokes \(em the keystrokes are stored
 as a macro.  When already recording, the recording is stopped.
 .TP
 .B runmacro
@@ -949,7 +949,7 @@ When writing a file, switches to writing a Mac format.
 When writing a file, appends to the end instead of overwriting.
 .TP
 .B prepend
-When writing a file, 'prepends' (writes at the beginning) instead of overwriting.
+When writing a file, "prepends" (writes at the beginning) instead of overwriting.
 .TP
 .B backup
 When writing a file, creates a backup of the current file.
@@ -1002,7 +1002,7 @@ Toggles the smartness of the Home key.
 .TP
 .B autoindent
 Toggles whether a newly created line will contain the same amount of leading
-whitespace as the preceding line -- or as the next line if the preceding line
+whitespace as the preceding line \(em or as the next line if the preceding line
 is the beginning of a paragraph.
 .TP
 .B cutfromcursor
@@ -1033,32 +1033,32 @@ The help-viewer menu.
 The search menu (AKA whereis).
 .TP
 .B replace
-The 'search to replace' menu.
+The \&'search to replace' menu.
 .TP
 .B replacewith
-The 'replace with' menu, which comes up after 'search to replace'.
+The \&'replace with' menu, which comes up after \&'search to replace'.
 .TP
 .B yesno
-The 'yesno' menu, where the Yes/No/All/Cancel question is asked.
+The \&'yesno' menu, where the Yes/No/All/Cancel question is asked.
 .TP
 .B gotoline
-The 'goto line (and column)' menu.
+The \&'goto line (and column)' menu.
 .TP
 .B writeout
-The 'write file' menu.
+The \&'write file' menu.
 .TP
 .B insert
-The 'insert file' menu.
+The \&'insert file' menu.
 .TP
 .B browser
-The 'file browser' menu, for selecting a file to be opened or
+The \&'file browser' menu, for selecting a file to be opened or
 inserted or written to.
 .TP
 .B whereisfile
-The 'search for a file' menu in the file browser.
+The \&'search for a file' menu in the file browser.
 .TP
 .B gotodir
-The 'go to directory' menu in the file browser.
+The \&'go to directory' menu in the file browser.
 .TP
 .B execute
 The menu for inserting the output from an external command,
@@ -1087,7 +1087,7 @@ To make \fBCtrl+Z\fR suspend nano:
 To make \fBShift+Alt+C\fR copy the marked region to the system's clipboard:
 .sp
 .RS
-.B bind Sh-M-C """{execute}| xsel -ib {enter}{undo}""" main
+.B bind Sh\-M\-C """{execute}| xsel \-ib {enter}{undo}""" main
 .RE
 .sp
 
@@ -1106,5 +1106,5 @@ Syntax definitions for the syntax coloring of common file types
 .SH SEE ALSO
 .BR nano (1)
 .TP
-.I https://nano-editor.org/cheatsheet.html
+.I https://nano\-editor.org/cheatsheet.html
 An overview of the default key bindings.