Add more code spans to docs in intrinsics.rs
I have added some more code spans in core/src/intrinsics.rs, changing some `=` to `==`, etc. I also changed the wording in some sections.
Constier maybe uninit
I was playing around trying to make `[T; N]::zip()` in #79451 be `const fn`. One of the things I bumped into was `MaybeUninit::assume_init`. Is there any reason for the intrinsic `assert_inhabited<T>()` and therefore `MaybeUninit::assume_init` not being `const`?
---
I have as best as I could tried to follow the instruction in [library/core/src/intrinsics.rs](https://github.com/rust-lang/rust/blob/master/library/core/src/intrinsics.rs#L11). I have no idea what I am doing but it seems to compile after some slight changes after the copy paste. Is this anywhere near how this should be done?
Also any ideas for name of the feature gate? I guess `const_maybe_assume_init` is quite misleading since I have added some more methods. Should I add test? If so what should be tested?
Part of #68490.
Care has been taken to leave the old consts where appropriate, for testing backcompat regressions, module shadowing, etc. The intrinsics docs were accidentally referring to some methods on f64 as std::f64, which I changed due to being contrary with how we normally disambiguate the shadow module from the primitive. In one other place I changed std::u8 to std::ops since it was just testing path handling in macros.
For places which have legitimate uses of the old consts, deprecated attributes have been optimistically inserted. Although currently unnecessary, they exist to emphasize to any future deprecation effort the necessity of these specific symbols and prevent them from being accidentally removed.
Also stabilize constctlz for const ctlz_nonzero.
The public methods stabilized const by this commit are:
* `{i*,u*}::checked_pow`
* `{i*,u*}::saturating_pow`
* `{i*,u*}::wrapping_pow`
* `{i*,u*}::overflowing_pow`
* `{i*,u*}::pow`
* `u*::next_power_of_two`
* `u*::checked_next_power_of_two`
* `u*::wrapping_next_power_of_two` (the method itself is still unstable)
`crate::` -> `core::`
It looks weird to have `crate::` in the link text and we use the actual
crate name everywhere else.
If anyone is curious, I used this Vim command to update all the links:
%s/\(\s\)\[`crate::\(.*\)`\]/\1[`core::\2`](crate::\2)/g
Move to intra-doc links for /library/core/src/intrinsics.rs
Helps with #75080.
@rustbot modify labels: T-doc, A-intra-doc-links, T-rustdoc
Known issues:
* The following f32 and f64 primitive methods cannot be resolved:
f32/f64::powi
f32/f64::sqrt
f32/f64::sin
f32/f64::cos
f32/f64::powf
f32/f64::exp
f32/f64::exp2
f32/f64::ln
f32/f64::log2
f32/f64::log10
f32/f64::mul_add
f32/f64::abs
f32/f64::copysign
f32/f64::floor
f32/f64::ceil
f32/f64::trunc
f32/f64::round
* Links from core to std:
[`std::pointer::*`]
[`std::process::abort`]
[`from_raw_parts`]
[`Vec::append`]
* Links with anchors?
I provided a separate commit that replaced links with anchors by intra-doc links.
Here the anchor location information gets lost, so its questionable whether to
actually replace those links.
