[agents] Link forked agent sessions back to their source

vrobbler/templates/agents/agentsession_detail.html

@@ -27,7 +27,7 @@
                 {% for scrobble in scrobbles %}
                 <tr>
                     <td><a href={{scrobble.get_absolute_url}}>{{scrobble.local_timestamp}}</a></td>
-                    <td>{{scrobble.logdata.title|truncatechars_html:80}}</td>
+                    <td>{{scrobble.logdata.title|truncatechars_html:80}}{% if scrobble.logdata.forked_from_id %}<br/><a class="text-muted small" href="{% url 'scrobbles:detail' scrobble.logdata.forked_from_id %}">&larr; forked from previous session</a>{% endif %}</td>
                     <td>{% if scrobble.logdata.turns %}{{scrobble.logdata.turns|length}}{% else %}—{% endif %}</td>
                 </tr>
                 {% endfor %}