[libcxx] [llvm] [libc++] Format the code base (PR #74334)

[Louis Dionne via llvm-commits]

ldionne wrote:

> @ldionne Would this new clang-format 18 option help: https://clang.llvm.org/docs/ClangFormatStyleOptions.html#allowbreakbeforenoexceptspecifier

Thanks for pointing this out, I wasn't aware of it! However, I am not sure it would fix our issues because it probably still wouldn't align the three identical bits of code. It feels like `clang-format` would almost need to learn about the write-it-three-times pattern in order to do a good job at this (and even then, some write-it-three-times expressions are so long that custom formatting is really needed).

https://github.com/llvm/llvm-project/pull/74334