Add link to source code in developer page.

Author: ntoll

en/developers.html

@@ -13,13 +13,15 @@ <h1>Mu Development</h1>
 
 <p>Our technical documentation is hosted on the wonderful
 service that is <a href="https://mu.readthedocs.io/en/latest/" target="_blank">Read the
-Docs (http://mu.readthedocs.io/)</a>.</p>
-
-<p>Not only does it contain details needed in order to make code
+Docs (http://mu.readthedocs.io/)</a>. Not only does it contain details needed
+in order to make code
 contributions to Mu, but it outlines plenty of other ways in which you can
 contribute (including making updates to this website). Finally it provides a
 guide to our processes and expectations for the various types of contribution
 you can make to Mu.</p>
 
+<p>The source code is <a href="https://github.com/mu-editor/mu">hosted on
+GitHub</a>.</p>
+
 <p>If in doubt, just <a href="/en/discuss">ask in our discussion area</a> and
 someone will be able to point you in the right direction.</p>