std: Fix rustdoc links with std::fmt::Alignment
std: Fix rustdoc links with std::fmt::Alignment

This is actually a reexported implementation detail in the `rt::v1` module but
rustdoc doesn't like reexporting items from `doc(hidden)` modules. Do what we'd
end up doing anyway from an API perspective and make a public-facing `enum` that
can be retranslated under the hood if necessary.

GBGamer/rust,graydon/rust,aidancully/rust,graydon/rust,GBGamer/rust,graydon/rust,graydon/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,graydon/rust,GBGamer/rust,GBGamer/rust,graydon/rust,aidancully/rust,aidancully/rust