fix: Correctly show heading in tabular template (#259)

Author: drikusroor

nested_admin/templates/nesting/admin/inlines/tabular.html

@@ -13,7 +13,7 @@
     <fieldset class="module djn-fieldset {{ inline_admin_formset.classes }}" aria-labelledby="{{ inline_admin_formset.formset.prefix }}-heading">
     {% if inline_admin_formset.is_collapsible %}<details><summary>{% endif %}
 
-    <h2 id="{{ inline_admin_formset.formset.prefix }}-heading" class="inline-heading"></h2>
+    <h2 id="{{ inline_admin_formset.formset.prefix }}-heading" class="inline-heading">
         {% if inline_admin_formset.opts.title %}{{ inline_admin_formset.opts.title }}{% else %}{{ inline_admin_formset.opts.verbose_name_plural|capfirst }}{% endif %}
     </h2>
     {% if inline_admin_formset.is_collapsible %}</summary>{% endif %}