Minor documentation soundness hole in `Validity`?

`Validity` requires:

> Any `V: Validity` must guarantee that this set is only a function of the bit validity of the referent type, `T`, and not of any other property of `T`.

...but `Valid`'s guarantees concern both bit validity *and* safety. By this documentation, a `Ptr::from_ref(&&42)` is unsound, since the validity of the referent `&42` depends its provenance, which isn't a property of bit validity.