Add a link-friendly name to the Clang extension acceptance criteria

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@135859 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/www/get_involved.html b/www/get_involved.html
index b3550a5..eb9a979 100644
--- a/www/get_involved.html
+++ b/www/get_involved.html
@@ -56,7 +56,7 @@
 
 <p>If you're looking for something to work on, check out our <a href="OpenProjects.html">Open Projects</a> page or go look through the <a href="http://llvm.org/bugs/">Bugzilla bug database</a>.</p>
 
-<h2>Contributing Extensions to Clang</h2>
+<h2 name="criteria">Contributing Extensions to Clang</h2>
 
 <p>Clang has always been designed as a platform for experimentation,
 allowing programmers to easily extend the compiler to support great