Add a line to ReleaseNotes for half float.

llvm-svn: 146939
diff --git a/llvm/docs/ReleaseNotes.html b/llvm/docs/ReleaseNotes.html
index 6159628..608a1f3 100644
--- a/llvm/docs/ReleaseNotes.html
+++ b/llvm/docs/ReleaseNotes.html
@@ -284,6 +284,7 @@
    expose new optimization opportunities:</p>
 
   <ul>
+    <li>IR support for half float</li>
     <li>....</li>
   </ul>
 </div>