Use grouped_field_set as variable name

Author: Cito

src/graphql/execution/execute.py

@@ -1388,11 +1388,11 @@ def collect_and_execute_subfields(
         )
 
         for sub_patch in sub_patches:
-            label, sub_patch_field_nodes = sub_patch
+            label, sub_patch_grouped_field_set = sub_patch
             self.execute_deferred_fragment(
                 return_type,
                 result,
-                sub_patch_field_nodes,
+                sub_patch_grouped_field_set,
                 label,
                 path,
                 incremental_data_record,