At some point between Rust 1.34.0 and 1.39.0, the ability to add documentation to reexported items was added, but I can't find it mentioned in either the RELEASE notes or the rust-lang.org blog posts.
Maybe this should be mentioned in the RELEASE notes for the version that added that feature?
I have a foo crate that I use to test stuff, and used cargo +1.39.0 doc to document this:
/// Ooooh, ghost!
pub use std::marker::PhantomData;
