Standardize `Range*` documentation
This updates the final example in the documentation for the types
`Range`, `RangeFrom`, `RangeFull`, `RangeInclusive`, `RangeTo`,
`RangeToInclusive`.
Use lifetime contravariance to elide more lifetimes in core+alloc+std
Sample:
```diff
- impl<'a, 'b, A: ?Sized, B: ?Sized> PartialEq<&'b mut B> for &'a mut A where A: PartialEq<B> {
+ impl<A: ?Sized, B: ?Sized> PartialEq<&mut B> for &mut A where A: PartialEq<B> {
#[inline]
- fn eq(&self, other: &&'b mut B) -> bool { PartialEq::eq(*self, *other) }
+ fn eq(&self, other: &&mut B) -> bool { PartialEq::eq(*self, *other) }
#[inline]
- fn ne(&self, other: &&'b mut B) -> bool { PartialEq::ne(*self, *other) }
+ fn ne(&self, other: &&mut B) -> bool { PartialEq::ne(*self, *other) }
}
```
[I didn't know this worked](https://internals.rust-lang.org/t/why-can-you-use-different-unconstrained-lifetimes-to-implement-traits/9544/2?u=scottmcm) until recently, but since defining methods contravariantly in their lifetimes this way has worked back to Rust 1.0, we might as well take advantage of combining it with IHLE.
Fix documentation of from_ne_bytes and from_le_bytes
Copypasta mistake, the documentation of `from_ne_bytes` and `from_le_bytes` used the big-endian variant in the example snippets.
Expand docs for `TryFrom` and `TryInto`.
The examples are still lacking for now, both for module docs and for methods/impl's. Will be adding those in further pushes.
Should hopefully resolve the doc concern in #33417 when finished?
In the `issue-53548` test added in this commit, the `Box<dyn Trait>`
type is expanded to `Box<dyn Trait + 'static>`, but the generator
"witness" that results is `for<'r> { Box<dyn Trait + 'r> }`. The WF
code was encountering an ICE (when debug-assertions were enabled) and
an unexpected compilation error (without debug-asserions) when trying
to process this `'r` region bound. In particular, to be WF, the region
bound must meet the requirements of the trait, and hence we got
`for<'r> { 'r: 'static }`. This would ICE because the `Binder`
constructor we were using was assering that no higher-ranked regions
were involved (because the WF code is supposed to skip those). The
error (if debug-asserions were disabled) came because we obviously
cannot prove that `'r: 'static` for any region `'r`. Pursuant with
our "lazy WF" strategy for higher-ranked regions, the fix is not to
require that `for<'r> { 'r: 'static }` holds (this is also analogous
to what we would do for higher-ranked regions appearing within the
trait in other positions).
