[Component-DI] Removed useless return

Author: saro0h

components/dependency_injection/tags.rst

@@ -199,8 +199,6 @@ To begin with, change the ``TransportChain`` class::
             if (array_key_exists($alias, $this->transports)) {
                return $this->transports[$alias];
             }
-
-            return;
         }
     }