Self-Review Checklist:

- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [ ] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

Improves https://github.com/zed-industries/zed/pull/57500 by including
an icon for the SourceHut remote. SourceHut provides the official icon
as a public domain licensed icon. I additionally got a permission from
Drew DeVault.

Amends the PR: https://github.com/zed-industries/zed/pull/57500

<img width="1407" height="444" alt="image"
src="https://github.com/user-attachments/assets/81a156f1-d94d-4c01-98b8-40e787e93112"
/>


No AI was used in the development of this feature, as is declared by
signing off the commits.

Release Notes:

- Added the SourceHut remote icon

Signed-off-by: medzernik <medzernik@medzernik.dev>