Rollup merge of #130350 - RalfJung:strict-provenance, r=dtolnay

stabilize Strict Provenance and Exposed Provenance APIs

Given that [RFC 3559](https://rust-lang.github.io/rfcs/3559-rust-has-provenance.html) has been accepted, t-lang has approved the concept of provenance to exist in the language. So I think it's time that we stabilize the strict provenance and exposed provenance APIs, and discuss provenance explicitly in the docs:
```rust
// core::ptr
pub const fn without_provenance<T>(addr: usize) -> *const T;
pub const fn dangling<T>() -> *const T;
pub const fn without_provenance_mut<T>(addr: usize) -> *mut T;
pub const fn dangling_mut<T>() -> *mut T;
pub fn with_exposed_provenance<T>(addr: usize) -> *const T;
pub fn with_exposed_provenance_mut<T>(addr: usize) -> *mut T;

impl<T: ?Sized> *const T {
    pub fn addr(self) -> usize;
    pub fn expose_provenance(self) -> usize;
    pub fn with_addr(self, addr: usize) -> Self;
    pub fn map_addr(self, f: impl FnOnce(usize) -> usize) -> Self;
}

impl<T: ?Sized> *mut T {
    pub fn addr(self) -> usize;
    pub fn expose_provenance(self) -> usize;
    pub fn with_addr(self, addr: usize) -> Self;
    pub fn map_addr(self, f: impl FnOnce(usize) -> usize) -> Self;
}

impl<T: ?Sized> NonNull<T> {
    pub fn addr(self) -> NonZero<usize>;
    pub fn with_addr(self, addr: NonZero<usize>) -> Self;
    pub fn map_addr(self, f: impl FnOnce(NonZero<usize>) -> NonZero<usize>) -> Self;
}
```

I also did a pass over the docs to adjust them, because this is no longer an "experiment". The `ptr` docs now discuss the concept of provenance in general, and then they go into the two families of APIs for dealing with provenance: Strict Provenance and Exposed Provenance. I removed the discussion of how pointers also have an associated "address space" -- that is not actually tracked in the pointer value, it is tracked in the type, so IMO it just distracts from the core point of provenance. I also adjusted the docs for `with_exposed_provenance` to make it clear that we cannot guarantee much about this function, it's all best-effort.

There are two unstable lints associated with the strict_provenance feature gate; I moved them to a new [strict_provenance_lints](https://github.com/rust-lang/rust/issues/130351) feature since I didn't want this PR to have an even bigger FCP. ;)

`@rust-lang/opsem` Would be great to get some feedback on the docs here. :)
Nominating for `@rust-lang/libs-api.`

Part of https://github.com/rust-lang/rust/issues/95228.

[FCP comment](https://github.com/rust-lang/rust/pull/130350#issuecomment-2395114536)

1 files changed, 2 insertions, 2 deletions

diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs
index 3ab65238368..8c1a3c76829 100644
--- a/library/std/src/lib.rs
+++ b/library/std/src/lib.rs
@@ -279,6 +279,8 @@
 //
 // Language features:
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(strict_provenance))]
+#![cfg_attr(not(bootstrap), feature(strict_provenance_lints))]
 #![feature(alloc_error_handler)]
 #![feature(allocator_internals)]
 #![feature(allow_internal_unsafe)]
@@ -336,7 +338,6 @@
 #![feature(error_iter)]
 #![feature(exact_size_is_empty)]
 #![feature(exclusive_wrapper)]
-#![feature(exposed_provenance)]
 #![feature(extend_one)]
 #![feature(float_gamma)]
 #![feature(float_minimum_maximum)]
@@ -362,7 +363,6 @@
 #![feature(slice_range)]
 #![feature(std_internals)]
 #![feature(str_internals)]
-#![feature(strict_provenance)]
 #![feature(strict_provenance_atomic_ptr)]
 #![feature(ub_checks)]
 // tidy-alphabetical-end