The macro that opts out of `std::ranges::` functionality is called
`_LIBCPP_HAS_NO_INCOMPLETE_RANGES`, and is unrelated to this macro
which is specifically about _compiler_ support for the _syntax_.
The only non-mechanical diff here is in `<__config>`.
Differential Revision: https://reviews.llvm.org/D118507
As prefigured in the comments on D115315.
This gives us one unified style for all niebloids,
and also simplifies the modulemap.
Differential Revision: https://reviews.llvm.org/D116570