Fix overflow of long domain names on topic listing

tildes/scss/modules/_topic.scss

@@ -212,6 +212,11 @@
   white-space: nowrap;
 }
 
+.topic-info-source {
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+
 .topic-full {
   .topic-voting {
     float: right;

tildes/tildes/templates/macros/topics.jinja2

@@ -79,11 +79,13 @@
         </a>
       </div>
 
+      <div class="topic-info-source"
       {% if topic.is_user_treated_as_source %}
-        <div aria-label="Posted by">{{ username_linked(topic.user.username) }}</div>
+        aria-label="Posted by">{{ username_linked(topic.user.username) }}
       {% else %}
-        <div aria-label="Link domain">{{ topic.link_domain }}</div>
+        aria-label="Link domain">{{ topic.link_domain }}
       {% endif %}
+      </div>
 
       <div aria-label="Post time">{{ adaptive_date_responsive(topic.created_time, precision=1) }}</div>
     </footer>