Mention quadratic voting in docs

Author: alandefreitas

docs/overrides/main.html

@@ -8,7 +8,7 @@
             ⭐️ Star {{ config.site_name }}
         </a>
         <a href="https://www.patreon.com/modernhpc" title="{{ config.site_name }}" class="md-button" target="_blank">
-            ❤️ Contribute to {{ config.site_name }}
+            ❤️ Quadratic Voting
         </a>
     </footer>
 {% endblock %}
@@ -43,4 +43,4 @@
             </div>
         </div>
     </div>
-{% endblock %}
+{% endblock %}