make ->get consistent with the doctrine way (by using class name)

Author: epitre

components/workflow.rst

@@ -84,7 +84,7 @@ you can retrieve a workflow from it and use it as follows::
     // ...
     // Consider that $blogPost is in place "draft" by default
     $blogPost = new BlogPost();
-    $workflow = $registry->get($blogPost);
+    $workflow = $registry->get(BlogPost::class);
 
     $workflow->can($blogPost, 'publish'); // False
     $workflow->can($blogPost, 'to_review'); // True

workflow.rst

@@ -253,7 +253,7 @@ registry in the constructor::
 
         public function toReview(BlogPost $post)
         {
-            $workflow = $this->workflowRegistry->get($post);
+            $workflow = $this->workflowRegistry->get(BlogPost::class);
 
             // Update the currentState on the post
             try {
@@ -665,7 +665,7 @@ of domain logic in your templates:
 
 ``workflow_has_marked_place()``
     Returns ``true`` if the marking of the given object has the given state.
-    
+
 ``workflow_transition_blockers()``
     Returns :class:`Symfony\\Component\\Workflow\\TransitionBlockerList` for the given transition.
 
@@ -700,7 +700,7 @@ The following example shows these functions in action:
     {% if 'reviewed' in workflow_marked_places(post) %}
         <span class="label">Reviewed</span>
     {% endif %}
-    
+
     {# Loop through the transition blockers #}
     {% for blocker in workflow_transition_blockers(post, 'publish') %}
         <span class="error">{{ blocker.message }}</span>
@@ -833,7 +833,7 @@ Then you can access this metadata in your controller as follows::
 
     public function myAction(Registry $registry, BlogPost $post)
     {
-        $workflow = $registry->get($post);
+        $workflow = $registry->get(BlogPost::class);
 
         $title = $workflow
             ->getMetadataStore()