search: Improve performance of replace_all (#13654)

Previously replace_all amounted to what could be achieved by repeatedly
mashing "Replace" button, which had a bunch of overhead related to
buffer state syncing. This commit gets rid of the automated button
mashing, processing all of the replacements in one go.

Fixes #13455



Release Notes:

- Improved performance of "replace all" in buffer search and project
search

crates/search/src/buffer_search.rs

@@ -1122,9 +1122,7 @@ impl BufferSearchBar {
                             .as_ref()
                             .clone()
                             .with_replacement(self.replacement(cx));
-                        for m in matches {
-                            searchable_item.replace(m, &query, cx);
-                        }
+                        searchable_item.replace_all(&mut matches.iter(), &query, cx);
                     }
                 }
             }

crates/search/src/project_search.rs

@@ -591,9 +591,7 @@ impl ProjectSearchView {
         }
 
         self.results_editor.update(cx, |editor, cx| {
-            for item in &match_ranges {
-                editor.replace(item, &query, cx);
-            }
+            editor.replace_all(&mut match_ranges.iter(), &query, cx);
         });
 
         self.model.update(cx, |model, _cx| {