Add missing indicator for submission topics

scipost_django/submissions/templates/submissions/_hx_submission_topics.html

@@ -54,6 +54,7 @@
 	      hx-post="{% url 'ontology:_hx_topic_dynsel_list' %}"
 	      hx-trigger="keyup delay:200ms, change"
 	      hx-target="#submission-{{ submission.id }}-topic-search-results"
+	      hx-indicator="#submission-{{ submission.pk }}-topics-indicator"
 	>
 	  <div id="submission-{{ submission.id }}-topic-search-form"
 	       class="mb-0"
@@ -62,6 +63,14 @@
 	  </div>
 	</form>
 	<div id="submission-{{ submission.pk }}-topic-search-results" class="border border-light m-2 p-1"></div>
+	<div id="submission-{{ submission.id }}-topics-indicator"
+	     class="htmx-indicator p-2"
+	>
+	  <button class="btn btn-sm btn-warning" type="button" disabled>
+	    <strong>Loading...</strong>
+	    <div class="spinner-grow spinner-grow-sm ms-2" role="status" aria-hidden="true"></div>
+	  </button>
+	</div>
       </div>
     </div>
   {% endif %}