linkme fails to ensure slice elements match the slice's declared type

Summary

Affected versions allow populating a DistributedSlice of T with elements of an arbitrary other type that coerces to T. For example, elements of type `&&str` could end up in a slice of type `[&str]`, since `&&str` coerces to `&str` via a deref coercion. The flaw was corrected by implementing typechecking for distributed slice elements in such a way that coercion no longer occurs. The element's type must be a subtype of the slice's declared element type.