[libcxx] [llvm] [libc++] LWG3870: Remove `voidify` (PR #110355)

[Michael Buch via llvm-commits]

Michael137 wrote:

> @Michael137 That's not a problem. Do you need a revert in the meantime to fix LLDB?
> 
> #110570

>From a quick glance at the formatter implementation, I think the fix should be pretty simple. Let me try locally and get back to you if I can't resolve this today

https://github.com/llvm/llvm-project/pull/110355