Tweak archive notice and provide link to site source

Author: Firefishy

site/layouts/_default/baseof.html

@@ -22,8 +22,8 @@
       </div>
       <div class="clear"></div>
       <div id="announcement">
-        This is a static archive of our old OSM Help Site.
-        Please post any new questions and answers at <a href="https://community.openstreetmap.org/">community.openstreetmap.org</a>.
+        This is a static archive of our old OpenStreetMap Help Site.
+        Please post any new questions and answers at <a href="https://community.openstreetmap.org/">community.osm.org</a>.
       </div>
       {{ block "main" . }}
       {{ end }}
@@ -43,6 +43,12 @@
         </a>
         Content on this site is licensed under a <a href="http://creativecommons.org/licenses/by-sa/2.0/legalcode">Creative Commons Attribution Share Alike 2.0</a> license.
       </div>
+      <div>
+        Source code available on
+        <a href="https://github.com/openstreetmap/help-website">
+          GitHub
+        </a>.
+      </div>
     </div>
 
   </body>