Rollup merge of #135805 - DiuDiu777:master, r=Noratrieb

Add missing allocator safety in alloc crate

### PR Description
In the previous PR [#135009](rust-lang/rust#135009), PR [#134496](rust-lang/rust#134496), some incomplete API documentation issues have been fixed.

Based on these changes,  other inconsistencies related to the allocator have also been identified, including:

- `Box::from_non_null`
- `Box::from_non_null_in`
- `Weak::from_raw`

Author: matthiaskrgr