Revert "Issue #2625138 by Oleksiy, almaudoh:...

Revert "Issue #2625138 by Oleksiy, almaudoh: EntityRepository::loadEntityByUuid() implementation does not match EntityRepositoryInterface::loadEntityByUuid() @return documentation"

This reverts commit 8d6a091a.

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

@@ -22,8 +22,8 @@ interface EntityRepositoryInterface {
    * @param string $uuid
    *   The UUID of the entity to load.
    *
-   * @return \Drupal\Core\Entity\EntityInterface|false
-   *   The entity object, or FALSE if there is no entity with the given UUID.
+   * @return \Drupal\Core\Entity\EntityInterface|null
+   *   The entity object, or NULL if there is no entity with the given UUID.
    *
    * @throws \Drupal\Core\Entity\EntityStorageException
    *   Thrown in case the requested entity type does not support UUIDs.