…signals, r=yaahc

std: `<ExitStatus as Display>::fmt` name the signal it died from

Related to rust-lang#95601

…=GuillaumeGomez

rustdoc: Add more test coverage

Related issue rust-lang#91113

update explicit impls error msg

…ding-where-clauses, r=lcnr

Fix wrong suggestion for adding where clauses

closes rust-lang#97576

don't use a `span_note` for ignored impls

Searching for the `derive` isn't too difficult as it's right above the field definition.

By using a span these errors are a lot more verbose than they should be, which is especially annoying as one can end up with a lot of `dead_code` warnings.

…n-docs, r=thomcc

Improve documentation for constructors of pinned `Box`es

Adds a cross-references between `Box::pin` and `Box::into_pin` (and other related methods, i.e. the equivalent `From` implementation, and the unstable `pin_in` method), in particular now that `into_pin` [was stabilized](rust-lang#97397). The main goal is to further improve visibility of the fact that `Box<T> -> Pin<Box<T>>` conversion exits in the first place, and that `Box::pin(x)` is – essentially – just a convenience function for `Box::into_pin(Box::new(x))`

The motivating context why I think this is important is even experienced Rust users overlooking the existence this kind of conversion, [e.g. in this thread on IRLO](https://internals.rust-lang.org/t/pre-rfc-function-variants/16732/7?u=steffahn); and also the fact that that discussion brought up that there would be a bunch of Box-construction methods "missing" such as e.g. methods with fallible allocation a la "`Box::try_pin`", and similar; while those are in fact *not* necessary, because you can use `Box::into_pin(Box::try_new(x)?)` instead.

I have *not* included explicit mention of methods (e.g. `try_new`) in the docs of stable methods (e.g. `into_pin`). (Referring to unstable API in stable API docs would be bad style IMO.) Stable examples I have in mind with the statement "constructing a (pinned) Box in a different way than with `Box::new`" are things like cloning a `Box`, or `Box::from_raw`. If/when `try_new` would get stabilized, it would become a very good concrete example use-case of `Box::into_pin` IMO.