Add release notes entry

Author: vvuksanovic

clang/docs/ReleaseNotes.rst

@@ -716,6 +716,10 @@ Improvements to Clang's diagnostics
   Added a new warning in this group for the case where the attribute is missing/implicit on
   an override of a virtual method.
 
+- Fixed false positives in ``-Waddress-of-packed-member`` diagnostics when
+  potential misaligned members get processed before they can get discarded.
+  (#GH144729)
+
 Improvements to Clang's time-trace
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