Adde release notes

Author: GeorgeKA

clang/docs/ReleaseNotes.rst

@@ -358,6 +358,7 @@ Bug Fixes to C++ Support
 - Fixed a Clang regression in C++20 mode where unresolved dependent call expressions were created inside non-dependent contexts (#GH122892)
 - Clang now emits the ``-Wunused-variable`` warning when some structured bindings are unused
   and the ``[[maybe_unused]]`` attribute is not applied. (#GH125810)
+- Clang now emits a warning when class template argument deduction for alias templates is used in C++17. (#GH133806)
 
 Bug Fixes to AST Handling
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