Rollup merge of rust-lang#143059 - jieyouxu:slice-as-chunks, r=cuviper

Fix 1.88 relnotes

- Use stable std links for `impl Default for {*const,*mut} T`
- Add missing relnotes for rust-lang#139656
    ```rs
    impl [T] {
        const fn as_chunks<const N: usize>(&self) -> (&[[T; N]], &[T]);
        const fn as_rchunks<const N: usize>(&self) -> (&[T], &[[T; N]]);
        const unsafe fn as_chunks_unchecked<const N: usize>(&self) -> &[[T; N]];
        const fn as_chunks_mut<const N: usize>(&mut self) -> (&mut [[T; N]], &mut [T]);
        const fn as_rchunks_mut<const N: usize>(&mut self) -> (&mut [T], &mut [[T; N]]);
        const unsafe fn as_chunks_unchecked_mut<const N: usize>(&mut self) -> &mut [[T; N]];
    }
    ```
- Add missing `mod ffi::c_str` and `hint::select_unpredictable`

r? `@cuviper`

Author: compiler-errors

RELEASES.md

@@ -54,16 +54,24 @@ Stabilized APIs
 ---------------
 
 - [`Cell::update`](https://doc.rust-lang.org/stable/std/cell/struct.Cell.html#method.update)
-- [`impl Default for *const T`](https://doc.rust-lang.org/nightly/std/primitive.pointer.html#impl-Default-for-*const+T)
-- [`impl Default for *mut T`](https://doc.rust-lang.org/nightly/std/primitive.pointer.html#impl-Default-for-*mut+T)
+- [`impl Default for *const T`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#impl-Default-for-*const+T)
+- [`impl Default for *mut T`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#impl-Default-for-*mut+T)
 - [`HashMap::extract_if`](https://doc.rust-lang.org/stable/std/collections/struct.HashMap.html#method.extract_if)
 - [`HashSet::extract_if`](https://doc.rust-lang.org/stable/std/collections/struct.HashSet.html#method.extract_if)
+- [`hint::select_unpredictable`](https://doc.rust-lang.org/stable/std/hint/fn.select_unpredictable.html)
 - [`proc_macro::Span::line`](https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.line)
 - [`proc_macro::Span::column`](https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.column)
 - [`proc_macro::Span::start`](https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.start)
 - [`proc_macro::Span::end`](https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.end)
 - [`proc_macro::Span::file`](https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.file)
 - [`proc_macro::Span::local_file`](https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.local_file)
+- [`<[T]>::as_chunks`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_chunks)
+- [`<[T]>::as_chunks_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_chunks_mut)
+- [`<[T]>::as_chunks_unchecked`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_chunks_unchecked)
+- [`<[T]>::as_chunks_unchecked_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_chunks_unchecked_mut)
+- [`<[T]>::as_rchunks`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_rchunks)
+- [`<[T]>::as_rchunks_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_rchunks_mut)
+- [`mod ffi::c_str`](https://doc.rust-lang.org/stable/std/ffi/c_str/index.html)
 
 These previously stable APIs are now stable in const contexts: