Update url of the TheoraCookbook at Flossmanuals.

git-svn-id: https://svn.xiph.org/websites/theora.org@17963 0101bb08-14d6-0310-b084-bc0e0c8e3800

doc/index.shtml.en

@@ -23,7 +23,7 @@
 </ul>
 
 <ul>
-  <li><a href="http://en.flossmanuals.net/TheoraCookbook/">Theora Cookbook</a> at FLOSS Manuals</li>
+  <li><a href="http://www.flossmanuals.net/ogg-theora/">Theora Cookbook</a> at FLOSS Manuals</li>
 </ul>
 
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