Issue #3221062 by SylvainM, joachim: DocBlock for...

Issue #3221062 by SylvainM, joachim: DocBlock for EntityDefinitionUpdateManagerInterface::getEntityType() missing NULL return

core/lib/Drupal/Core/Entity/EntityDefinitionUpdateManagerInterface.php

@@ -107,8 +107,8 @@ public function getChangeList();
    * @param string $entity_type_id
    *   The entity type identifier.
    *
-   * @return \Drupal\Core\Entity\EntityTypeInterface
-   *   The entity type definition.
+   * @return \Drupal\Core\Entity\EntityTypeInterface|null
+   *   The entity type definition. Or NULL if not found.
    */
   public function getEntityType($entity_type_id);