rustdoc: hide `#[repr]` if it isn't part of the public ABI
> [!IMPORTANT]
> Temporarily stacked on top of PR https://github.com/rust-lang/rust/pull/146527; only the last commit is relevant!
Follow-up to rust-lang/rust#115439.
Unblocks rust-lang/rust#116743, CC ``@dtolnay.``
Fixesrust-lang/rust#66401.
Fixesrust-lang/rust#128364.
Fixesrust-lang/rust#137440.
Only display the representation `#[repr(REPR)]` (where `REPR` is not `Rust` or `transparent`) of a given type if none of its variants (incl. the synthetic variants of structs) are `#[doc(hidden)]` and all of its fields are public and not `#[doc(hidden)]` since it's likely not meant to be considered part of the public ABI otherwise.
`--document-{private,hidden}-items` works as expected in this context, too.
Moreover, we now also factor in the presence of `#[doc(hidden)]` when checking whether to show `repr(transparent)` or not.
[rustdoc] Display unsafe attrs with edition 2024 `unsafe()` wrappers.
Use Rust 2024 edition representation for unsafe attributes in rustdoc HTML:
- `#[no_mangle]` -> `#[unsafe(no_mangle)]`
- `#[export_name = "foo"]` -> `#[unsafe(export_name = "foo")]`
- `#[link_section = ".text"]` -> `#[unsafe(link_section = ".text")]`
The 2024 edition representation is used regardless of the crate's own edition. This ensures that Rustaceans don't have to learn the rules of an outdated edition (e.g. that `unsafe()` wasn't always necessary) in order to understand a crate's documentation.
After some looking through the `T-rustdoc` issues, I was not able to find an existing issue for this. Apologies if I missed it.
r? ``````@aDotInTheVoid``````
