Use GitHub spelling consistently

Author: kevinsawicki

index.html

@@ -54,7 +54,7 @@ <h2 style="margin-top: 0">Supported modes:</h2>
       <li><a href="mode/jinja2/index.html">Jinja2</a></li>
       <li><a href="mode/less/index.html">LESS</a></li>
       <li><a href="mode/lua/index.html">Lua</a></li>
-      <li><a href="mode/markdown/index.html">Markdown</a> (<a href="mode/gfm/index.html">Github-flavour</a>)</li>
+      <li><a href="mode/markdown/index.html">Markdown</a> (<a href="mode/gfm/index.html">GitHub-flavour</a>)</li>
       <li><a href="mode/mysql/index.html">MySQL</a></li>
       <li><a href="mode/ntriples/index.html">NTriples</a></li>
       <li><a href="mode/ocaml/index.html">OCaml</a></li>
@@ -194,7 +194,7 @@ <h2 id="support">Support and bug reports</h2>
 
   <p>Though bug reports through e-mail are responded to, the preferred
   way to report bugs is to use
-  the <a href="http://github.com/marijnh/CodeMirror/issues">Github
+  the <a href="http://github.com/marijnh/CodeMirror/issues">GitHub
   issue tracker</a>. Before reporting a
   bug, <a href="doc/reporting.html">read these pointers</a>. Also,
   the issue tracker is for <em>bugs</em>, not requests for help.</p>