[libcxx-commits] [libcxx] [libc++] Add the __is_replaceable type trait (PR #132408)

[Mark de Wever via libcxx-commits]

https://github.com/mordante commented:

A question is this intended to be [P2786R12](https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2025/p2786r13.html)'s `is_replaceable`? Is so can you add that to the commit message?

https://github.com/llvm/llvm-project/pull/132408