Add dismiss buffer search button & fix some faulty icon button styling

Co-Authored-By: Nate Butler <nate@zed.dev>

crates/gpui/src/app.rs

@@ -4038,7 +4038,7 @@ pub struct RenderContext<'a, T: View> {
     pub refreshing: bool,
 }
 
-#[derive(Clone, Default)]
+#[derive(Debug, Clone, Default)]
 pub struct MouseState {
     hovered: bool,
     clicked: Option<MouseButton>,