unused_extern_crates: wrong suggestion for aliased crate

[ehuss]

The following suggests converting to a use, but that causes it to fail to compile because use does not insert into the prelude.

#![warn(unused_extern_crates)]

extern crate time as time_crate;  // Suggests replacing with `use`.

pub mod m {
    pub use time_crate::Duration;   // But this will fail to compile.
}

Perhaps the suggestion should be removed if there is a rename?

rustc 1.33.0-nightly (2fadb0a 2019-01-13)
(This is after uniform-paths and the #57557 fix.)

[sunjay]

Related case of what seems to be the same issue as this: #60222

(Thanks to @ehuss for pointing that out)