Closes #51309

Before you mark this PR as ready for review, make sure that you have:
- [X] Added a solid test coverage and/or screenshots from doing manual
testing
- [X] Done a self-review taking into account security and performance
aspects
- [X] Aligned any UI changes with the [UI
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)

Release Notes:

- Improved `editor::CopyFileLocation` command to include the full
selected line range (e.g. 'src/main.rs:12-18') when multiple lines are
selected, rather than only the first line number.