Reduce allocations (#30693)

Removes a unnecessary string conversion and some clones

Release Notes:

- N/A

crates/file_finder/src/new_path_prompt.rs

@@ -354,8 +354,9 @@ impl PickerDelegate for NewPathDelegate {
         let m = self.matches.get(self.selected_index)?;
         if m.is_dir(self.project.read(cx), cx) {
             let path = m.relative_path();
-            self.last_selected_dir = Some(path.clone());
-            Some(format!("{}/", path))
+            let result = format!("{}/", path);
+            self.last_selected_dir = Some(path);
+            Some(result)
         } else {
             None
         }