Start work on documenting the conf file

docs/conf.rst

@@ -1,25 +1,32 @@
+:tocdepth: 2
+
 Configuring kitty
 ===============================
 
+.. highlight:: ini
+
 |kitty| is highly customizable, everything from keyboard shortcuts, to painting
-frames-per-second. See the heavily commented default config file below for an
-overview of all customization possibilities.
+frames-per-second. See below for an overview of all customization
+possibilities.
 
 You can open the config file within kitty by pressing |sc_edit_config_file|.
 You can also display the current configuration by running ``kitty
 --debug-config``.
 
-
-
-.. literalinclude:: ../kitty/kitty.conf
-    :language: ini
-
-
 .. _confloc:
 
 |kitty| looks for a config file in the OS config directories (usually
-:file:`~/.config/kitty/kitty.conf` and additionally
-:file:`~/Library/Preferences/kitty/kitty.conf` on macOS) but you can pass a
-specific path via the :option:`kitty --config` option or use the ``KITTY_CONFIG_DIRECTORY``
-environment variable. See the :option:`kitty --config` option
-for full details.
+:file:`~/.config/kitty/kitty.conf`) but you can pass a specific path via the
+:option:`kitty --config` option or use the ``KITTY_CONFIG_DIRECTORY``
+environment variable. See the :option:`kitty --config` option for full details.
+
+You can include secondary config files via the :code:`include` directive.  If
+you use a relative path for include, it is resolved with respect to the
+location of the current config file. Note that environment variables are
+expanded, so :code:`${USER}.conf` becomes :file:`name.conf` if
+:code:`USER=name`.  For example::
+
+     include other.conf
+
+
+.. include:: /generated/conf-kitty.rst