[NFC][Clang] Remove release note since the patch was backported in time

Author: royjacobson

clang/docs/ReleaseNotes.rst

@@ -58,8 +58,7 @@ C++ Specific Potentially Breaking Changes
 
 ABI Changes in This Version
 ---------------------------
-- ``__is_trivial`` has changed for a small category of classes with constrained default constructors (`#60697 <https://github.com/llvm/llvm-project/issues/60697>`_).
-  *FIXME: Remove this note if we've backported this change to the Clang 16 branch.*
+
 
 What's New in Clang |release|?
 ==============================