Issue #3301950 by szloredan: Add the label singular for entity type

src/Entity/SitewideAlert.php

@@ -23,6 +23,7 @@ use Drupal\user\UserInterface;
  * @ContentEntityType(
  *   id = "sitewide_alert",
  *   label = @Translation("Sitewide Alert"),
+ *   label_singular = @Translation("Sitewide Alert"),
  *   label_plural = @Translation("Sitewide Alerts"),
  *   label_collection = @Translation("Sitewide Alerts"),
  *   handlers = {