network.html: add sorting tip only when table is larger than one element

templates/network.html

@@ -72,7 +72,11 @@ active
               (<a href="/net/{{entry.name}}?full=True">full</a>)
             </div>
         {% endif %}
-        <span style="font-size:x-small">Tip: click on the table header to sort the list. Hover your mouse over it to obtain a legend.</span>
+        {% if entry.files|length > 1 %}
+            <span style="font-size:x-small">Tip: click on the table header to sort the list. Hover your mouse over it to obtain a legend.</span>
+        {% else %}
+            <span style="font-size:x-small">Tip: hover your mouse over a table header to obtain a legend.</span>
+        {% endif %}
         <table class="ink-table hover sortable" style="table-layout: auto">
           <thead>
             <tr>