Adding ADT SortedVector; client patch will follow.

llvm-svn: 243386
diff --git a/llvm/docs/ProgrammersManual.rst b/llvm/docs/ProgrammersManual.rst
index 08cc61a..fbc6332 100644
--- a/llvm/docs/ProgrammersManual.rst
+++ b/llvm/docs/ProgrammersManual.rst
@@ -1314,7 +1314,8 @@
 std::multiset is useful if you're not interested in elimination of duplicates,
 but has all the drawbacks of :ref:`std::set <dss_set>`.  A sorted vector
 (where you don't delete duplicate entries) or some other approach is almost
-always better.
+always better. LLVM actually offers SortedVector which does the job of a sorted
+std::vector.
 
 .. _ds_map: