This documentation-only change clarifies how the user can get the
string representation of the output of a command.

The `stdout` and `stderr` members of `std::process::Output` from 
`std::process::Command` return a Vec<u8>, which is not always what 
the user wants.

For simple cases like printing `stderr` iff the `std::process::ExitStatus`
is non-zero, it's useful to get the string representation of this `Vec<u8>`.
This can be done via `String::from_utf8_lossy`, but it's not clear that this
is possible from the documentation without first searching the internet for
an answer.

Link to playground: https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=8189f65dc4b354a643311af2cea5b230

This is needed for my Ubuntu 22.04 box due to a slight change in gdb
output. The fix is similar to the fix in rust-lang#95063.

Improves the compiler error backtrace information, as shown in rust-lang#99363,
by using `span_bug` instead of `bug`.

New output:

```
build/aarch64-apple-darwin/stage1/bin/rustc /tmp/test.rs --edition=2021
error: internal compiler error: compiler/rustc_middle/src/ty/closure.rs:185:25: Unexpected type Opaque(DefId(0:5 ~ test[db0f]::main::T::{opaque#0}), []) for `Field` projection
  --> /tmp/test.rs:11:27
   |
11 |         let Foo((a, b)) = foo;
   |                           ^^^

thread 'rustc' panicked at 'Box<dyn Any>', /Users/jmq/src/forked/rust/compiler/rustc_errors/src/lib.rs:1331:9
stack backtrace:
```

(Remainder of output truncated.)

The restriction that success ordering must be at least as strong as its
failure ordering in compare-exchange operations was lifted in rust-lang#98383.

docs: show how to stringify the output of Command

This documentation-only change clarifies how the user can get the string representation of the output of a command.

The `stdout` and `stderr` members of `std::process::Output` from `std::process::Command` return a Vec<u8>, which is not always what the user wants.

For simple cases like printing `stderr` iff the `std::process::ExitStatus` is non-zero, it's useful to get the string representation of this `Vec<u8>`. This can be done via `String::from_utf8_lossy`, but it's not clear that this is possible from the documentation without first searching the internet for an answer.

Link to playground: https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=8189f65dc4b354a643311af2cea5b230

Use split_once in FromStr docs

Current implementation:

```rust
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let coords: Vec<&str> = s.trim_matches(|p| p == '(' || p == ')' )
                                 .split(',')
                                 .collect();

        let x_fromstr = coords[0].parse::<i32>()?;
        let y_fromstr = coords[1].parse::<i32>()?;

        Ok(Point { x: x_fromstr, y: y_fromstr })
    }
```

Creating the vector is not necessary, `split_once` does the job better.

Alternatively we could also remove `trim_matches` with `strip_prefix` and `strip_suffix`:

```rust
        let (x, y) = s
            .strip_prefix('(')
            .and_then(|s| s.strip_suffix(')'))
            .and_then(|s| s.split_once(','))
            .unwrap();
```

The question is how much 'correctness' is too much and distracts from the example. In a real implementation you would also not unwrap (or originally access the vector without bounds checks), but implementing a custom Error and adding a `From<ParseIntError>` and implementing the `Error` trait adds a lot of code to the example which is not relevant to the `FromStr` trait.

use body's param-env when checking if type needs drop

The type comes from the body, so we should be using the body's param-env, as opposed to the ADT's param env, because we know less in the latter compared to the former.

Fixes rust-lang#99375

…pnkfelix

Fix debuginfo tests.

This is needed for my Ubuntu 22.04 box due to a slight change in gdb
output. The fix is similar to the fix in rust-lang#95063.

Use span_bug for unexpected field projection type

Improves the compiler error backtrace information, as shown in rust-lang#99363,
by using `span_bug` instead of `bug`.

New output:

```
build/aarch64-apple-darwin/stage1/bin/rustc /tmp/test.rs --edition=2021
error: internal compiler error: compiler/rustc_middle/src/ty/closure.rs:185:25: Unexpected type Opaque(DefId(0:5 ~ test[db0f]::main::T::{opaque#0}), []) for `Field` projection
  --> /tmp/test.rs:11:27
   |
11 |         let Foo((a, b)) = foo;
   |                           ^^^

thread 'rustc' panicked at 'Box<dyn Any>', /Users/jmq/src/forked/rust/compiler/rustc_errors/src/lib.rs:1331:9
stack backtrace:
```

(Remainder of output truncated.)

Update invalid atomic ordering lint

The restriction that success ordering must be at least as strong as its
failure ordering in compare-exchange operations was lifted in rust-lang#98383.

…=Mark-Simulacrum

Stabilize `core::task::ready!`

This stabilizes `core::task::ready!` for Rust 1.64. The FCP for stabilization was just completed here rust-lang#70922 (comment). Thanks!

Closes rust-lang#70922

cc/ `@rust-lang/libs-api`