Use spacing to distinguish what is related to a given heading.

The previous setup did not properly consider hyperthreads (at least in local
testing), which likely skews CI results as well. The new code is both simpler
and hopefully will produce more accurate results.

Clarify error on casting larger integers to char

Closes rust-lang#91836 with changes to E0604.md and a `span_help`.

…clibceabi, r=nagisa

Add new target armv7-unknown-linux-uclibceabi (softfloat)

This adds the new target `armv7-unknown-linux-uclibceabi (softfloat)`. It is of course similar to `armv7-unknown-linux-uclibceabihf (hardfloat)` which was just recently added to rust except that it is `softfloat`.

My interest lies in the Broadcom BCM4707/4708/BCM4709 family, notably found in some Netgear and Asus consumer routers. The armv7 Cortex-A9 cpus found in these devices do not have an fpu or NEON support.

With this patch I've been able to bootstrap rustc, std and host tools `(extended = true)` to run on the target device for native compilation, allowing the target to be used as a development platform.

With the recent addition of `armv7-unknown-linux-uclibceabihf (hardfloat)` it looks like many of the edge cases of using the uclibc c-library are getting worked out nicely. I've been able to compile some complex projects. Some patching still needed in some crates, but getting there for sure.  I think `armv7-unknown-linux-uclibceabi` is ready to be a tier 3 target.

I use a cross-toolchain from my project to bootstrap rust.
https://github.com/lancethepants/tomatoware
The goal of this project is to create a native development environment with support for various languages.

Remove "up here" arrow on item-infos

Use spacing to distinguish what is related to a given heading.

This was originally introduced in rust-lang#53043, in response to rust-lang#51387. The arrow is a little distracting, and leads the item-info to not be aligned properly with the text below it.

Demo: https://rustdoc.crud.net/jsha/impl-spacing/std/string/struct.String.html

r? `@GuillaumeGomez`

Change struct expr pretty printing to match rustfmt style

This PR backports trailing comma support from https://github.com/dtolnay/prettyplease into rustc_ast_pretty and uses it to improve the formatting of struct expressions.

Example:

```rust
macro_rules! stringify_expr {
    ($expr:expr) => {
        stringify!($expr)
    };
}

fn main() {
    println!("{}", stringify_expr!(Struct {
        a: Struct { b, c },
    }));
    println!("{}", stringify_expr!(Struct {
        aaaaaaaaaa: AAAAAAAAAA,
        bbbbbbbbbb: Struct {
            cccccccccc: CCCCCCCCCC,
            dddddddddd: DDDDDDDDDD,
            eeeeeeeeee: EEEEEEEEEE,
        },
    }));
}
```

🤮 Before:

```console
Struct{a: Struct{b, c,},}
Struct{aaaaaaaaaa: AAAAAAAAAA,
    bbbbbbbbbb:
        Struct{cccccccccc: CCCCCCCCCC,
            dddddddddd: DDDDDDDDDD,
            eeeeeeeeee: EEEEEEEEEE,},}
```

After:

```console
Struct { a: Struct { b, c } }
Struct {
    aaaaaaaaaa: AAAAAAAAAA,
    bbbbbbbbbb: Struct {
        cccccccccc: CCCCCCCCCC,
        dddddddddd: DDDDDDDDDD,
        eeeeeeeeee: EEEEEEEEEE,
    },
}
```

… r=oli-obk

Add regression tests for issue 80309

Closes rust-lang#80309 😝

I'm not sure where to put the tests, is `ui/issues` the right place for this kind of tests?

…r=pietroalbini

Update CPU idle tracking for apple hosts

The previous setup did not properly consider hyperthreads (at least in local
testing), which likely skews CI results as well. The new code is both simpler
and hopefully will produce more accurate results; locally it matches behavior
of the Linux version of this script.

…atic_rustdoc, r=GuillaumeGomez

Refactor conditional

Merge two `if` in just one.

… r=lcnr

Resolve lifetimes for const generic defaults

We weren't visiting the const generic default argument in `rustc_resolve::late::lifetimes`. This seems to fix the issue, and we deny any non-`'static` lifetimes anyways.

Fixes rust-lang#93647