Closes https://github.com/zed-industries/zed/issues/58580

* Outline modal and panel now use buffer fonts for the contents:

<img width="1728" height="1117" alt="modal"
src="https://github.com/user-attachments/assets/5e0ef6e3-be39-4949-bc32-7087a51a02ec"
/>
<img width="1728" height="1092" alt="panel"
src="https://github.com/user-attachments/assets/5cf9edbf-5ff3-402d-a2ca-bc915bd10e8e"
/>

* Gutter colors are now fall-backed to tree-sitter better, if no
semantic tokens could be retrieved due to multi buffer shenanigans:

<img width="1728" height="426" alt="gutter"
src="https://github.com/user-attachments/assets/a175b2c8-843e-4632-b030-3edfbd350982"
/>

Release Notes:

- Improved outline fonts and colors