public function submitForm(array &$form, FormStateInterface $form_state) {
$link = $form['#plugin_form']->submitConfigurationForm($form, $form_state);
- drupal_set_message($this->t('The menu link has been saved.'));
+ $this->messenger()->addStatus($this->t('The menu link has been saved.'));
$form_state->setRedirect(
'entity.menu.edit_form',
['menu' => $link->getMenuName()]