Actually I will just mention this one in the Ideas section for future developers.
Allow when cursor is in a line for comment toggle to use a single line comment symbols, and when multiple lines are hightlight and user uses comment toggle that it uses multi line comment symbols, both based on the current documents coding language used.
Thank You
As explained on #3997 it is risky that the delimiting comments nest safely. Probably not a good idea.
github-comments@lists.geany.org