fix: Say when no IRSG ballots exist (#4788)

Fixes #4749

ietf/templates/doc/irsg_ballot_status.html

@@ -10,6 +10,7 @@
 {% block content %}
     {% origin %}
     <h1>IRSG ballot status</h1>
+    {% if docs %}
         <table class="table table-sm table-striped tablesorter">
             <thead>
                 <tr>
@@ -17,7 +18,6 @@
                     <th scope="col" data-sort="status">Status</th>
                 </tr>
             </thead>
-        {% if docs %}
                 <tbody>
                     {% for doc in docs %}
                         <tr>
@@ -26,8 +26,12 @@
                         </tr>
                     {% endfor %}
                 </tbody>
-        {% endif %}
         </table>
+    {% else %}
+        <p class="alert alert-info my-3">
+            No open IRSG ballots.
+        </p>
+    {% endif %}
 {% endblock %}
 {% block js %}
     <script src="{% static "ietf/js/list.js" %}"></script>