Auto merge of #76311 - lzutao:split_core-slice, r=lcnr

Split `core::slice` to smaller mods

Unfortunately the `#[lang = "slice"]` is too big (3003 lines), I cannot split it further.

Note for reviewer:
* I split to multiple commits for easier reviewing, but I could git squash them all to one if requested.
* Recommend pulling this change locally and using advanced git diff viewer or this command:
  ```
  git show --reverse --color-moved=dimmed-zebra master..
  ```

---

I split core/slice/mod.rs to these modules:

* `ascii`: For operations on `[u8]`.
* `cmp`: For comparison operations on `[T]`, like PartialEq and SliceContains impl.
* `index`: For indexing operations like Index/IndexMut and SliceIndex.
* `iter`: For Iterator definitions and implementation on `[T]`.
  - `macros`: For iterator! and forward_iterator! macros.
* `raw`: For free function to create `&[T]` or `&mut [T]` from pointer + length or a reference.

The heapsort wrapper in mod.rs is removed in favor of reexport from `sort::heapsort`.

0 files changed, 0 insertions, 0 deletions