[libc++][ranges][NFC] Added P2711R1 to release notes

[H-G-Hristov]

Summary

This adds release notes for P2711R.
join_with_view is missing an implementation yet.

Implemented in: https://reviews.llvm.org/D144822

[Mordante]

LGTM modulo one comment.

libcxx/docs/Status/Cxx2bPapers.csv

111 ↗

(On Diff #523278)

Typically we only ad versions when things are done.

[H-G-Hristov]

• Addressed comments

libcxx/docs/ReleaseNotes.rst

 
 Implemented Papers
 ------------------
 - P2520R0 - ``move_iterator<T*>`` should be a random access iterator
 - P1328R1 - ``constexpr type_info::operator==()``
 - P1413R3 - Formatting ``thread::id`` (the ``stacktrace`` is not done yet)
 - P2675R1 - ``format``'s width estimation is too approximate and not forward compatible
 - P2505R5 - Monadic operations for ``std::expected``
+- P2711R1 - Making Multi-Param Constructors Of views explicit (``join_with_view`` is not done yet)
 
 Improvements and New Features
 -----------------------------
 - ``std::equal`` and ``std::ranges::equal`` are now forwarding to ``std::memcmp`` for integral types and pointers,
   which can lead up to 40x performance improvements.
 
 - ``std::string_view`` now provides iterators that check for out-of-bounds accesses when the safe
   libc++ mode is enabled.