Closes #51622

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
- [ ] Aligned any UI changes with the [UI
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)

Release Notes:

- Fixed markdown escape characters being visible in LSP diagnostic
messages when leading whitespace caused indented code blocks

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Co-authored-by: Smit Barmase <heysmitbarmase@gmail.com>