terminal: remove trailing comma

shiftregister/signage/templates/terminal.html

@@ -79,7 +79,7 @@
                             <td>{{shift.start_at}}</td>
                             <td>{{ shift.registration_count }}/{{ shift.required_helpers|default:shift.room.required_helpers }}</td>
                             <td>{{shift.room.name}} </td>
-                            <td><b>{%for item in shift.teambackup_set.all%}{{item.name}}, {%empty%}</b> <div class="has-text-danger">unbesetzt</div> <b>{%endfor%}</b></td>
+                            <td><b>{%for item in shift.teambackup_set.all%}{{item.name}}{% if not forloop.last %}, {% endif %}{%empty%}</b> <div class="has-text-danger">unbesetzt</div> <b>{%endfor%}</b></td>
                         </tr>
                         {% endfor %}
                     </tbody>