Add option select_by_word_characters_forward

This adds an option to select separate characters for forward and
backward word extension on double click. If it is empty the old behavior
is preserved. This is the default.

If it is not empty, select_by_word_characters_forward will be used for
extending the selection in forward direction (right) and
select_by_word_characters will be used for extending in backward
direction (left).

Signed-off-by: Konrad Gräfe <kgraefe@paktolos.net>

kitty/options/parse.py

@@ -1163,6 +1163,9 @@ class Parser:
     def select_by_word_characters(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
         ans['select_by_word_characters'] = str(val)
 
+    def select_by_word_characters_forward(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
+        ans['select_by_word_characters_forward'] = str(val)
+
     def selection_background(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
         ans['selection_background'] = to_color_or_none(val)