[llvm] [flang] [clang] [lld] [libc] [libcxx] [lldb] [clang-tools-extra] [compiler-rt] [libunwind] Reland: [libc++][format] P2637R3: Member visit (std::basic_format_arg) #76449 (PR #79032)

[Hristo Hristov via cfe-commits]

https://github.com/H-G-Hristov commented:

@mordante I guess the PR missed LLVM18 release. I'll update the release notes accordingly. Is that OK?

https://github.com/llvm/llvm-project/pull/79032