Add indications of where MD support is enabled as per comment by @samozzy in #178.

Isn't quite a full description, but for the most part this should be enough for the people who know how to use it see where they can use it.

templates/base.html

@@ -210,6 +210,7 @@
         easter_egg.load();
     });
 </script>
+<script src="{% static "js/tooltip.js" %}"></script>
 {% block js %}
 {% endblock %}
 </body>