Minor tweaks

Author: javiereguiluz

workflow/usage.rst

@@ -472,13 +472,11 @@ Transition Blockers
 -------------------
 
 .. versionadded:: 4.1
-    Transition Blockers were introduced in Symfony 4.1.
-
-Transition Blockers provide a simple way to return a human-readable message for why a transition
-was blocked. You can access the message from Twig. Here's an example:
 
+    Transition Blockers were introduced in Symfony 4.1.
 
-.. code-block:: php
+Transition Blockers provide a way to return a human-readable message for why a
+transition was blocked::
 
     use Symfony\Component\Workflow\Event\GuardEvent;
     use Symfony\Component\EventDispatcher\EventSubscriberInterface;
@@ -508,6 +506,8 @@ was blocked. You can access the message from Twig. Here's an example:
         }
     }
 
+You can access the message from a Twig template as follows:
+
 .. code-block:: html+twig
 
     <h2>Publication was blocked because:</h2>