Deprecate atomic::spin_loop_hint in favour of hint::spin_loop

[KodrAus]

For #55002

We wanted to leave atomic::spin_loop_hint alone when stabilizing hint::spin_loop so folks had some time to migrate. This now deprecates atomic_spin_loop_hint.

[rust-highfive]

r? @m-ou-se

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[rust-log-analyzer]

The job mingw-check failed! Check out the build log: (web) (plain)

Click to see the possible cause of the failure (guessed by this bot)

configure: rust.channel         := nightly
configure: rust.debug-assertions := True
configure: llvm.assertions      := True
configure: dist.missing-tools   := True
configure: build.configure-args := ['--enable-sccache', '--disable-manage-submodu ...
configure: writing `config.toml` in current directory
configure: 
configure: run `python /checkout/x.py --help`
configure: 
---
skip untracked path cpu-usage.csv during rustfmt invocations
skip untracked path src/doc/book/ during rustfmt invocations
skip untracked path src/doc/rust-by-example/ during rustfmt invocations
skip untracked path src/llvm-project/ during rustfmt invocations
Diff in /checkout/library/std/src/sys/hermit/mutex.rs at line 1:
Running `"/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/rustfmt" "--config-path" "/checkout" "--edition" "2018" "--unstable-features" "--skip-children" "--check" "/checkout/library/std/src/sys/hermit/mutex.rs"` failed.
If you're running `tidy`, try again with `--bless`. Or, if you just want to format code, run `./x.py fmt` instead.
 use crate::cell::UnsafeCell;
 use crate::collections::VecDeque;
 use crate::ffi::c_void;
+use crate::hint;
 use crate::ops::{Deref, DerefMut, Drop};
 use crate::ptr;
-use crate::hint;
 use crate::sync::atomic::{AtomicUsize, Ordering};
 use crate::sys::hermit::abi;
failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test --stage 2 src/tools/tidy
Build completed unsuccessfully in 0:00:19

[m-ou-se]

@bors r+

[bors]

📌 Commit d65cb6e has been approved by m-ou-se