[Clang] Update ReleaseNotes.rst

Author: tinnamchoi

clang/docs/ReleaseNotes.rst

@@ -125,6 +125,7 @@ Improvements to Clang's diagnostics
   an override of a virtual method.
 - Fixed fix-it hint for fold expressions. Clang now correctly places the suggested right 
   parenthesis when diagnosing malformed fold expressions. (#GH151787)
+- Added fix-it hint for when scoped enumerations require explicit conversions for binary operations. (#GH24265)
 
 Improvements to Clang's time-trace
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