Add changelog

Author: Fznamznon

clang/docs/ReleaseNotes.rst

@@ -210,6 +210,8 @@ Bug Fixes in This Version
 
 - Clang now outputs correct values when #embed data contains bytes with negative
   signed char values (#GH102798).
+- Fixed rejects-valid problem when #embed appears in std::initializer_list or
+  when it can affect template argument deduction (#GH122306).
 
 Bug Fixes to Compiler Builtins
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