ui: More component previews, UI component cleanup (#25302)

- Don't require ui component docs (this isn't really working)
- Add more component previews
- Update component preview style & navigation

Release Notes:

- N/A

crates/ui/src/components/tooltip.rs

@@ -1,5 +1,3 @@
-#![allow(missing_docs)]
-
 use gpui::{Action, AnyElement, AnyView, AppContext as _, FocusHandle, IntoElement, Render};
 use settings::Settings;
 use theme::ThemeSettings;