rust-lang#46001

…ol, r=frewsxcv

rustdoc book: talk about #![doc(test(no_crate_inject))] and #![doc(test(attr(...)))]

While investigating rust-lang#45750 i noticed that `#![doc(test(attr(...)))]` wasn't documented at all. Since this is useful for making your examples follow the same coding guidelines as your code, i wanted to add it to the Rustdoc Book. I also added `#![doc(test(no_crate_inject))]` since it's used in the same place and might be useful for macro-heavy crates. I added mentions for these to "The `doc` attribute" as well as "Documentation tests" since it's useful information in both places.

Technically the step reordering in the second commit is gated on rust-lang#45764, since before that lands attributes from the doctest come before the ones from `#![doc(test(attr(...)))]`.

fix some python3 incompatibilities

…QuietMisdreavus

Fix primitive types not showing up

Fixes rust-lang#46017.

r? @QuietMisdreavus

Remove return_ty from Mir

rust-lang#46001