Closes #29544

Fixes an issue where accepting an HTML completion would correctly edit
the start tag but incorrectly update the end tag due to incorrect linked
edit ranges.

I want to handle multi cursor case (as it barely works now), but seems
like this should go first. As, it might need whole `do_completions`
overhaul.

Todo:
- [x] Tests for completion aceept on linked edits

Before:


https://github.com/user-attachments/assets/917f8d2a-4a0f-46e8-a004-675fde55fe3d

After:


https://github.com/user-attachments/assets/84b760b6-a5b9-45c4-85d8-b5dccf97775f

Release Notes:

- Fixes an issue where accepting an HTML completion would correctly edit
the start tag but incorrectly update the end tag.