mention AddressSanitizer in 3.1 release notes

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146505 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/ReleaseNotes.html b/docs/ReleaseNotes.html
index c20cf74..4d2f5c4 100644
--- a/docs/ReleaseNotes.html
+++ b/docs/ReleaseNotes.html
@@ -263,6 +263,7 @@
 <p>LLVM 3.1 includes several major changes and big features:</p>
 
 <ul>
+  <li><a href="../tools/clang/docs/AddressSanitizer.html">AddressSanitizer</a>, a fast memory error detector.</li>
   <li>....</li>
 </ul>