Rollup merge of #113657 - Urgau:expand-incorrect_fn_null_check-lint, r=cjgillot

Expand, rename and improve `incorrect_fn_null_checks` lint

This PR,

 - firstly, expand the lint by now linting on references
 - secondly, it renames the lint `incorrect_fn_null_checks` -> `useless_ptr_null_checks`
 - and thirdly it improves the lint by catching `ptr::from_mut`, `ptr::from_ref`, as well as `<*mut _>::cast` and `<*const _>::cast_mut`

Fixes rust-lang/rust#113601
cc ```@est31```

Author: matthiaskrgr