Add more detail to panel switcher interaction (#3344)

Also featuring:
* IconButton#action()
* gpui::ManagedView
* `menu_handle()`

Release Notes:

- N/A
391ab8fa1bConrad Irwin committed on 11/17/2023, 6:16:50 AM· committed by GitHubparentse67c44a2d1d75f
22 files changedLine totals unavailable