Just one void invoices button is sufficient thanks

And yes, this is changing it back to a button; having it as a link
isn't quite what we want.

pinaxcon/templates/dashboard.html

@@ -125,9 +125,9 @@
                                 <a href="{% url "invoice" invoice.id %}" >Invoice {{ invoice.id }}</a>
                                 - ${{ invoice.value }} ({{ invoice.get_status_display }})
                                 </li>
-                                <a id="toggle-void-invoices" href="" onclick="toggleVoidInvoices();">Show void invoices</a>
                             {% endfor %}
                           </ul>
+                          <a id="toggle-void-invoices" href="#" onclick="toggleVoidInvoices();">Show void invoices</a>
                         </div>
                       </div>
                     </div>