Closes #ISSUE Before you mark this PR as ready for review, make sure that you have: - [ ] Added a solid test coverage and/or screenshots from doing manual testing - [ ] Done a self-review taking into account security and performance aspects - [ ] Aligned any UI changes with the [UI checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist) Release Notes: - Improved the behavior of the `vim: join lines` and `editor: join lines`. Comment and other language specific line prefixes are now stripped from the join line