Add a release note for r372844

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@372846 91177308-0d34-0410-b5e6-96231b3b80d8

docs/ReleaseNotes.rst

@@ -102,7 +102,18 @@ Attribute Changes in Clang
 Windows Support
 ---------------
 
-- ...
+- Previous Clang versions contained a work-around to avoid an issue with the
+  standard library headers in Visual Studio 2019 versions prior to 16.3. This
+  work-around has now been removed, and users of Visual Studio 2019 are
+  encouraged to upgrade to 16.3 or later, otherwise they may see link errors as
+  below:
+
+  .. code-block:: console
+
+    error LNK2005: "bool const std::_Is_integral<int>" (??$_Is_integral@H@std@@3_NB) already defined
+
+
+
 
 C Language Changes in Clang
 ---------------------------