feat: add debugging-call

Author: janbritz

classes/local/attempt_ui/question_ui_renderer.php

@@ -280,6 +280,7 @@ private function set_input_values_and_readonly(question_attempt $attempt): void
             $name = $element->getAttribute('name');
             if (!$name || $name === 'data') {
                 // The name 'data' is reserved for storing dynamic data and is not related to an input element.
+                debugging('The name of an input element cannot be "data".');
                 continue;
             }