Merge branch '4.2'

* 4.2:
  Missing square bracket
  Update kernel.rst

Author: javiereguiluz

components/cache.rst

@@ -116,7 +116,7 @@ recompute::
     $beta = 1.0;
     $value = $cache->get('my_cache_key', function (ItemInterface $item) {
         $item->expiresAfter(3600);
-        $item->tag(['tag_0', 'tag_1');
+        $item->tag(['tag_0', 'tag_1']);
 
         return '...';
     }, $beta);

reference/configuration/kernel.rst

@@ -182,7 +182,6 @@ achieve a strict reproducible build:
     .. code-block:: php
 
         // config/services.php
-        use Symfony\Component\DependencyInjection\Reference;
 
         // ...
         $container->setParameter('kernel.container_build_time', '1234567890');