{% regroup messages by category as type_list %}

{% for type in type_list %}
<ul class="{{ type.grouper }} messages">
{% for message in type.list %}
  <li>{{ message|safe }}</li>
{% endfor %}
</ul>
{% endfor %}

{% for message in messages %}
<ul class="messages">
  <li>{{ message|safe }}</li>
</ul>
{% endfor %}