Merge branch '5.2' into 5.3

* 5.2:
  [5.2] Add missing `@return` annotations
  [4.4] Add missing `@return` annotations
  Handle lock with long key
  #42227 update phpdoc to recommend createIndex over ensureIndex

Author: nicolas-grekas

Loader/Configurator/CollectionConfigurator.php

@@ -38,6 +38,9 @@ public function __construct(RouteCollection $parent, string $name, self $parentC
         $this->parentPrefixes = $parentPrefixes;
     }
 
+    /**
+     * @return array
+     */
     public function __sleep()
     {
         throw new \BadMethodCallException('Cannot serialize '.__CLASS__);

Loader/Configurator/ImportConfigurator.php

@@ -30,6 +30,9 @@ public function __construct(RouteCollection $parent, RouteCollection $route)
         $this->route = $route;
     }
 
+    /**
+     * @return array
+     */
     public function __sleep()
     {
         throw new \BadMethodCallException('Cannot serialize '.__CLASS__);