This PR updates the `borrow_as_ptr` lint to no longer suggest `addr_of!`
and `addr_of_mut!` and instead use the preferred `&raw const` and `&raw
mut` syntax.
Not sure about two things:
1. Do I need to set or update a MSRV for the lint anywhere?
2. There is a `borrow_as_ptr_no_std` test as well as a `borrow_as_ptr`
test. They used to be more relevant as the lint needed to select `std`
or `core`, but that is gone now, so maybe the `borrow_as_ptr_no_std`
should be deleted?
changelog: update `borrow_as_ptr` to suggest `&raw` syntax