update release notes

Author: a-tarasyuk

clang/docs/ReleaseNotes.rst

@@ -525,7 +525,8 @@ Attribute Changes in Clang
 
 - The ``target_version`` attribute is now only supported for AArch64 and RISC-V architectures.
 
-- Clang now permits ``[[msvc::constexpr]]`` usage outside of the std namespace. (#GH74924)
+- Clang now permits the usage of the placement new operator in ``[[msvc::constexpr]]``
+  context outside of the std namespace. (#GH74924)
 
 Improvements to Clang's diagnostics
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