gpui_linux: split xkbcommon wayland/x11 features (#60834)

# Objective

When xkbcommon compiled with either wayland or x11 only, the current
manifests will prevent it from compiling, despite gpui is already
wayland/x11 seperated.

close #60943 

## Solution

Simple changes to manifests.

## Testing

```
 cargo tree -p gpui_platform --no-default-features --features {wayland,x11} -e features -i xkbcommon
```

## Self-Review Checklist:

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

Release Notes:

- N/A

Co-authored-by: Kirill Bulatov <kirill@zed.dev>
afc13dc8e0xhe committed on 7/14/2026, 12:47:50 PM· committed by GitHubparent9554ea5
1 file changedLine totals unavailable