Add a release note

Author: dalg24

libcxx/docs/ReleaseNotes/21.rst

@@ -39,6 +39,7 @@ Implemented Papers
 ------------------
 
 - N4258: Cleaning-up noexcept in the Library (`Github <https://github.com/llvm/llvm-project/issues/99937>`__)
+- P3323R1: cv-qualified types in ``atomic`` and ``atomic_ref`` (`Github <https://github.com/llvm/llvm-project/issues/118378>`__)
 
 Improvements and New Features
 -----------------------------

libcxx/docs/Status/Cxx2cPapers.csv

@@ -87,7 +87,7 @@
 "`P3050R2 <https://wg21.link/P3050R2>`__","Fix C++26 by optimizing ``linalg::conjugated`` for noncomplex value types","2024-11 (Wrocław)","","",""
 "`P3396R1 <https://wg21.link/P3396R1>`__","``std::execution`` wording fixes","2024-11 (Wrocław)","","",""
 "`P2835R7 <https://wg21.link/P2835R7>`__","Expose ``std::atomic_ref``'s object address","2024-11 (Wrocław)","","",""
-"`P3323R1 <https://wg21.link/P3323R1>`__","cv-qualified types in ``atomic`` and ``atomic_ref``","2024-11 (Wrocław)","|Complete|","20","Implemented as DR against C++20."
+"`P3323R1 <https://wg21.link/P3323R1>`__","cv-qualified types in ``atomic`` and ``atomic_ref``","2024-11 (Wrocław)","|Complete|","21","Implemented as DR against C++20."
 "`P3508R0 <https://wg21.link/P3508R0>`__","Wording for ""constexpr for specialized memory algorithms""","2024-11 (Wrocław)","","",""
 "`P3369R0 <https://wg21.link/P3369R0>`__","constexpr for ``uninitialized_default_construct``","2024-11 (Wrocław)","","",""
 "`P3370R1 <https://wg21.link/P3370R1>`__","Add new library headers from C23","2024-11 (Wrocław)","","",""