Z-2303 editor: fix comment extension on the start of line (#2595)

Release Notes:

- Improved comment extension for cases where cursor was placed before
start of comment marker
5bef2f1778Piotr Osiewicz committed on 6/9/2023, 6:02:51 PM· committed by GitHubparentfb83ab8
2 files changedLine totals unavailable