[FOLD] add release note

Author: sdkrystian

clang/docs/ReleaseNotes.rst

@@ -190,6 +190,7 @@ Bug Fixes to C++ Support
 - Fix init-capture packs having a size of one before being instantiated. (#GH63677)
 - Clang now preserves the unexpanded flag in a lambda transform used for pack expansion. (#GH56852), (#GH85667),
   (#GH99877).
+- Fixed a bug when diagnosing ambiguous explicit specializations of constrained member functions.
 
 Bug Fixes to AST Handling
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