cells: add block in forms_of_category.html to make customization easier (#40883)

combo/apps/wcs/templates/combo/wcs/forms_of_category.html

@@ -1,8 +1,7 @@
 {% load assets i18n %}
 {% block cell-content %}
-
-{% block cell-header %}
 {% if forms or combo_display_even_empty_categories %}
+{% block cell-header %}
 <h2>{{ title }}</h2>
 {% include "combo/asset_picture_fragment.html" %}
 {% if description %}
@@ -10,11 +9,10 @@
 {{ description|safe }}
 </div>
 {% endif %}
-{% endif %}
 {% endblock %}
 
-{% if forms or combo_display_even_empty_categories %}
 <div class="wcs-forms-of-category-{{slug}}">
+{% block cell-top-content %}{% endblock cell-top-content %}
 <ul>
 {% for form in forms %}
 <li class="{{ form.css_classes|join:" " }}"