Add new dotted and dashed underline enum

Also use "straight" for single underline, consistent with the protocol
extension document.

kittens/tui/operations.py

@@ -170,7 +170,7 @@ STANDARD_COLORS = {name: i for i, name in enumerate(
     'black red green yellow blue magenta cyan gray'.split())}
 STANDARD_COLORS['white'] = STANDARD_COLORS['gray']
 UNDERLINE_STYLES = {name: i + 1 for i, name in enumerate(
-    'straight double curly'.split())}
+    'straight double curly dotted dashed'.split())}
 
 
 ColorSpec = Union[int, str, Color]

kitty/options/definition.py

@@ -360,7 +360,7 @@ opt('url_color', '#0087bd',
     option_type='to_color', ctype='color_as_int',
     long_text='''
 The color and style for highlighting URLs on mouse-over. :code:`url_style` can
-be one of: none, single, double, curly
+be one of: none, straight, double, curly, dotted, dashed
 '''
     )
 

kitty/options/utils.py

@@ -501,11 +501,14 @@ def scrollback_pager_history_size(x: str) -> int:
 
 
 def url_style(x: str) -> int:
+    # for backwards compat
+    if x == 'single':
+        x = 'straight'
     return url_style_map.get(x, url_style_map['curly'])
 
 
 url_style_map = {
-    v: i for i, v in enumerate('none single double curly'.split())
+    v: i for i, v in enumerate('none straight double curly dotted dashed'.split())
 }