linux: Update cosmic_text (#13095)

Bumps cosmic_text, removes some stale `todo`s and stores a ShapeBuffer
to prevent reallocations

Improvements:

- Performance should be a lot better (haven't actually tested it)
- Fixed display of `\t` in the terminal

![image](https://github.com/zed-industries/zed/assets/71973804/ca994912-851d-48ef-8dc7-b244c9eb484d)

![image](https://github.com/zed-industries/zed/assets/71973804/42fa9acf-ec10-4247-a5e3-2d4fe664ded6)


Release Notes:

- N/A