ruby: Mention `kanayago` and `fuzzy-ruby-server` in the documentation (#60640)

# Objective

Hi! This PR updates the Ruby doc to mention 2 language servers
`kanayago` and `fuzzy-ruby-server`.

## Testing

N/A

## 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 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
- [x] Performance impact has been considered and is acceptable

## Showcase

N/A

---

Release Notes:

- N/A
c93b4cd9ccVitaly Slobodin committed on 7/9/2026, 7:54:36 AM· committed by GitHubparent57261fe
1 file changedLine totals unavailable