Update workflow.rst

add a couple lines to example code for better understanding

Author: Chad Meyers

workflow.rst

@@ -317,6 +317,8 @@ workflow leaves a place::
 
     class WorkflowLogger implements EventSubscriberInterface
     {
+        private $logger;
+        
         public function __construct(LoggerInterface $logger)
         {
             $this->logger = $logger;
@@ -602,6 +604,8 @@ requires:
 
 Then you can access this metadata in your controller as follows::
 
+    use Symfony\Component\Workflow\Registry;
+
     public function myController(Registry $registry, Article $article)
     {
         $workflow = $registry->get($article);