use can_download flag for media front end messages

app/common/templates/errorbox.html

@@ -3,7 +3,7 @@
   <div class="col s12">
     <div class="card errorbox">
       <div class="card-content">
-        <i class="fas fa-exclamation-triangle"></i> {{ message|safe }}
+        <i class="fas fa-fw fa-exclamation-triangle"></i> {{ message|safe }}
       </div>
     </div>
   </div>

app/sync/templates/sync/media-item.html

@@ -10,6 +10,7 @@
     <p class="truncate">Saving to: <strong>{{ media.source.directory_path }}</strong></p>
   </div>
 </div>
+{% if not media.can_download %}{% include 'errorbox.html' with message='Media cannot be downloaded because it has no formats which match the source requirements.' %}{% endif %}
 <div class="row">
   <div class="col s12">
     <table class="striped">

app/sync/templates/sync/media.html

@@ -18,7 +18,7 @@
           <img src="{% if m.thumb %}{% url 'sync:media-thumb' pk=m.pk %}{% else %}{% static 'images/nothumb.png' %}{% endif %}">
           <span class="card-title truncate">{{ m.source }}<br>
             <span>{{ m.name }}</span><br>
-            <span>{{ m.published|date:'Y-m-d' }}</span>
+            <span>{% if m.can_download %}{{ m.published|date:'Y-m-d' }}{% else %}<i class="fas fa-exclamation-triangle"></i> No matching formats{% endif %}</span>
           </span>
         </div>
       </a>