Update docs/components/cache.rst

Co-authored-by: Ruth Cheesley <ruth@ruthcheesley.co.uk>

docs/components/cache.rst

@@ -52,6 +52,7 @@ Removing cache items
 Cache Pools include methods to delete a cache item, some of them, or all of them. The most common is ``Psr\\Cache\\CacheItemPoolInterface::deleteItem``, which deletes the cache item identified by the given key.
 
 .. code-block:: php
+
     $isDeleted = $cache->deleteItem('user_'.$userId);
 Use the ``Psr\\Cache\\CacheItemPoolInterface::deleteItems`` method to delete several cache items simultaneously - it returns true only if all the items have been deleted, even when any or some of them don't exist.