add release note

Author: HerrCai0907

clang/docs/ReleaseNotes.rst

@@ -338,6 +338,8 @@ Bug Fixes to C++ Support
 - Fix the parsing of variadic member functions when the ellipis immediately follows a default argument.(#GH153445)
 - Fixed a bug that caused ``this`` captured by value in a lambda with a dependent explicit object parameter to not be
   instantiated properly. (#GH154054)
+- Fixed a crash when implicit conversions from initialize list to arrays of
+  unknown bound during constant evaluation. (#GH151716)
 
 Bug Fixes to AST Handling
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