feat(trusted_asref): new lint

[niklasf]

Closes #10323.

Example:

unsafe { ffi(generic_bytes.as_ref().as_ptr(), generic_bytes.as_ref().len()) }

may be broken by pathological AsRef implementations using interior mutability.

While not all such uses are actually unsound (maybe ffi() does not actually require consistent arguments here, or maybe all possible AsRef implementations come from the same crate), the generated warnings should always be actionable and possibly prevent subtle soundness issues in the future.

Scanned crates.io and found 85 candidate crates, of which I so far manually confirmed 5/5 to be actually unsound. Intend to review more and individually submit fixes.

changelog: new lint: [trusted_asref]

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[github-actions]

Lintcheck changes for 0e8af49

Lint	Added	Removed	Changed
clippy::trusted_asref	4	0	0

This comment will be updated if you push new changes

[niklasf]

Btw. looks like the lintcheck findings from the pinned redox version were already fixed quite a while ago.