FormHelperTrait::addWarning(): use '#theme' => 'status_messages'
requested to merge issue/config_enforce-3337732:3337732-formhelpertrait-should-use-theme-status-messages into 1.0.x
This replaces '#type' => 'markup' with '#theme' => 'status_messages'
See https://www.drupal.org/project/config_enforce/issues/3337732