gpui: Unify track_scroll method to receive a reference type (#43518)
Release Notes:
- N/A
This PR to change the `track_scroll` method to receive a reference type
like the
[Div#track_scroll](https://docs.rs/gpui/latest/gpui/trait.StatefulInteractiveElement.html#method.track_scroll),
[Div#track_focus](https://docs.rs/gpui/latest/gpui/trait.InteractiveElement.html#method.track_focus).
```diff
- .track_scroll(self.scroll_handle.clone())
+ .track_scroll(&self.scroll_handle)
- .vertical_scrollbar_for(self.scroll_handle.clone(), window, cx)
+ .vertical_scrollbar_for(&self.scroll_handle, window, cx)
```
https://github.com/zed-industries/zed/blob/56a2f9cfcf0c6a3c38f596b58002953763cd890f/crates/gpui/src/elements/div.rs#L1088-L1093
https://github.com/zed-industries/zed/blob/56a2f9cfcf0c6a3c38f596b58002953763cd890f/crates/gpui/src/elements/div.rs#L613-L620
Jason Lee
1a23115773