Keep link icon for permalink from being ugly for screenreaders

This is a longer approach than what i think we'll take though

agaric/templates/content/comment.html.twig

@@ -89,7 +89,8 @@
       indicator here would break the render cache.
     #}
     <mark class="hidden is-primary" data-comment-timestamp="{{ new_indicator_timestamp }}"></mark>
-    <p><small>{{ permalink }}</small></p>
+
+    <p><small><a href="{{ url }}" class="u-url" rel="bookmark" title="Permalink"><ion-icon name="link" aria-hidden="true"></ion-icon><span class="visually-hidden">Permalink</a></small></p>
   </div>
   <div class="media-content">
     {% if title %}