Fix table of contents.

llvm-svn: 18727

llvm/docs/ReleaseNotes.html

@@ -19,6 +19,7 @@
   <ul>
     <li><a href="#experimental">Experimental features included in this
                                 release</a>
+    <li><a href="#build">Known problems with the LLVM Build</a>
     <li><a href="#core">Known problems with the LLVM Core</a>
     <li><a href="#c-fe">Known problems with the C Front-end</a>
     <li><a href="#c++-fe">Known problems with the C++ Front-end</a>