Auto merge of #91728 - Amanieu:stable_asm, r=joshtriplett

Stabilize asm! and global_asm!

Tracking issue: #72016

It's been almost 2 years since the original [RFC](rust-lang/rfcs#2850) was posted and we're finally ready to stabilize this feature!

The main changes in this PR are:
- Removing `asm!` and `global_asm!` from the prelude as per the decision in #87228.
- Stabilizing the `asm` and `global_asm` features.
- Removing the unstable book pages for `asm` and `global_asm`. The contents are moved to the [reference](rust-lang/reference#1105) and [rust by example](rust-lang/rust-by-example#1483).
  - All links to these pages have been removed to satisfy the link checker. In a later PR these will be replaced with links to the reference or rust by example.
- Removing the automatic suggestion for using `llvm_asm!` instead of `asm!` if you're still using the old syntax, since it doesn't work anymore with `asm!` no longer being in the prelude. This only affects code that predates the old LLVM-style `asm!` being renamed to `llvm_asm!`.
- Updating `stdarch` and `compiler-builtins`.
- Updating all the tests.

r? `@joshtriplett`

Author: bors

src/inline_asm.rs

@@ -1,4 +1,4 @@
-//! Codegen of [`asm!`] invocations.
+//! Codegen of `asm!` invocations.
 
 use crate::prelude::*;