ReleaseNotes: add note about ASTContext::WCharTy and WideCharTy

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@182280 91177308-0d34-0410-b5e6-96231b3b80d8

docs/ReleaseNotes.rst

@@ -126,6 +126,15 @@ in the source, the linkage and a semantic storage class. This was a bit
 redundant and the semantic storage class has been removed. The method
 getStorageClass now returns what is written it the source code for that decl.
 
+Wide Character Types
+^^^^^^^^^^^^^^^^^^^^
+
+The ASTContext class now keeps track of two different types for wide character
+types: WCharTy and WideCharTy. WCharTy represents the built-in wchar_t type
+available in C++. WideCharTy is the type used for wide character literals; in
+C++ it is the same as WCharTy, but in C99, where wchar_t is a typedef, it is an
+integer type.
+
 ...
 
 libclang