Cleanup: Add comment about purpose of add modifier operator

scripts/startup/bl_ui/properties_data_modifier.py

@@ -227,6 +227,7 @@ class AddModifierMenu(Operator):
 
     @classmethod
     def poll(cls, context):
+        # NOTE: This operator only exists to add a poll to the add modifier shortcut in the property editor.
         space = context.space_data
         return space and space.type == 'PROPERTIES' and space.context == "MODIFIER"