Add two points to release notes about recent command line library changes.

Patch by Dan Liew!

llvm-svn: 181335
diff --git a/llvm/docs/ReleaseNotes.rst b/llvm/docs/ReleaseNotes.rst
index 3689af1..cb60df7 100644
--- a/llvm/docs/ReleaseNotes.rst
+++ b/llvm/docs/ReleaseNotes.rst
@@ -73,6 +73,13 @@
 * MCJIT now supports exception handling. Support for it in the old jit will be
   removed in the 3.4 release.
 
+* Command line options can now be grouped into categories which are shown in
+  the output of ``-help``. See :ref:`grouping options into categories`.
+
+* The appearance of command line options in ``-help`` that are inherited by
+  linking with libraries that use the LLVM Command line support library can now
+  be modified at runtime. See :ref:`cl::getRegisteredOptions`.
+
 * ... next change ...
 
 .. NOTE