Auto merge of #55912 - kennytm:rollup, r=kennytm

Rollup of 20 pull requests

Successful merges:

 - #55136 (Remove short doc where it starts with a codeblock)
 - #55711 (Format BtreeMap::range_mut example)
 - #55722 (impl_stable_hash_for: support enums and tuple structs with generic parameters)
 - #55754 (Avoid converting bytes to UTF-8 strings to print, just pass bytes to stdout/err)
 - #55804 (rustdoc: don't inline `pub use some_crate` unless directly asked to)
 - #55805 (Move `static_assert!` into librustc_data_structures)
 - #55837 (Make PhantomData #[structural_match])
 - #55840 (Fix TLS errors when downloading stage0)
 - #55843 (add FromIterator<A> to Box<[A]>)
 - #55858 (Small fixes on code blocks in rustdoc)
 - #55863 (Fix a typo in std::panic)
 - #55870 (Fix typos.)
 - #55874 (string: Add documentation for `From` impls)
 - #55879 (save-analysis: Don't panic for macro-generated use globs)
 - #55882 (Reference count `crate_inherent_impls`s return value.)
 - #55888 (miri: for uniformity, also move memory_deallocated to AllocationExtra)
 - #55889 (global allocators: add a few comments)
 - #55896 (Document optimizations enabled by FusedIterator)
 - #55905 (Change `Lit::short_name` to `Lit::literal_name`.)
 - #55908 (Fix their/there grammar nit)

1 files changed, 4 insertions, 0 deletions

diff --git a/src/liballoc/alloc.rs b/src/liballoc/alloc.rs
index 3bd0c243b39..1a8a081e16f 100644
--- a/src/liballoc/alloc.rs
+++ b/src/liballoc/alloc.rs
@@ -21,6 +21,10 @@ use core::usize;
 pub use core::alloc::*;
 
 extern "Rust" {
+    // These are the magic symbols to call the global allocator.  rustc generates
+    // them from the `#[global_allocator]` attribute if there is one, or uses the
+    // default implementations in libstd (`__rdl_alloc` etc in `src/libstd/alloc.rs`)
+    // otherwise.
     #[allocator]
     #[rustc_allocator_nounwind]
     fn __rust_alloc(size: usize, align: usize) -> *mut u8;