Rust 1.78 (#11314)

Notable things I've had to fix due to 1.78:
- Better detection of unused items
- New clippy lint (`assigning_clones`) that points out places where assignment operations with clone rhs could be replaced with more performant `clone_into`
Release Notes:

- N/A

crates/search/src/buffer_search.rs

@@ -426,10 +426,6 @@ impl ToolbarItemView for BufferSearchBar {
         }
         ToolbarItemLocation::Hidden
     }
-
-    fn row_count(&self, _: &WindowContext<'_>) -> usize {
-        1
-    }
 }
 
 impl BufferSearchBar {

crates/search/src/project_search.rs

@@ -1629,15 +1629,6 @@ impl ToolbarItemView for ProjectSearchBar {
             ToolbarItemLocation::Hidden
         }
     }
-
-    fn row_count(&self, cx: &WindowContext<'_>) -> usize {
-        if let Some(search) = self.active_project_search.as_ref() {
-            if search.read(cx).filters_enabled {
-                return 2;
-            }
-        }
-        1
-    }
 }
 
 fn register_workspace_action<A: Action>(