Set flash translation domain

Author: Thomas Jarrand

Resources/views/components/flash.html.twig

@@ -1,7 +1,7 @@
 {% for label, messages in app.flashes %}
     {% for message in messages %}
         <div class="alert alert--{{ label }}">
-            {{ message.message|default(message)|trans(message.parameters|default({})) }}
+            {{ message.message|default(message)|trans(message.parameters|default({}), flash_translation_domain|default('flash')) }}
         </div>
     {% endfor %}
 {% endfor %}