Issue #3484587 by daniel.j, joachim, catch: Document that invalid IDs are not...

Issue #3484587 by daniel.j, joachim, catch: Document that invalid IDs are not present in the return array or EntityStorageInterface::loadMultiple

(cherry picked from commit 89fde027)

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

@@ -41,8 +41,8 @@ public function resetCache(?array $ids = NULL);
    *   An array of entity IDs, or NULL to load all entities.
    *
    * @return \Drupal\Core\Entity\EntityInterface[]
-   *   An array of entity objects indexed by their IDs. Returns an empty array
-   *   if no matching entities are found.
+   *   An array of successfully loaded objects indexed by their IDs.
+   *   Returns an empty array if no matching entities are found.
    */
   public function loadMultiple(?array $ids = NULL);