fix name of Twig function

cawolf · OskarStark · commit 930224a4bc6e · 2019-04-09T08:41:29.000+02:00
relates to symfony#11268
diff --git a/workflow/usage.rst b/workflow/usage.rst
@@ -516,7 +516,7 @@ You can access the message from a Twig template as follows:
                 <li>
                     <strong>{{ transition.name }}</strong>:
                     <ul>
-                    {% for blocker in workflow_build_transition_blocker_list(article, transition.name) %}
+                    {% for blocker in workflow_transition_blockers(article, transition.name) %}
                         <li>
                             {{ blocker.message }}
                             {% if blocker.parameters.expression is defined %}
