Add a configurable mouse action to select from the clicked point to the end of the line.

Fixes #3585

kitty/config.py

@@ -336,6 +336,7 @@ def mouse_selection(func: str, rest: str) -> FuncArgsType:
             'rectangle': defines.MOUSE_SELECTION_RECTANGLE,
             'word': defines.MOUSE_SELECTION_WORD,
             'line': defines.MOUSE_SELECTION_LINE,
+            'line_from_point': defines.MOUSE_SELECTION_LINE_FROM_POINT,
         }
         setattr(mouse_selection, 'code_map', cmap)
     return func, [cmap[rest]]