Broken links in docs due to reexports

Example:

[legion::EntityStore](https://docs.rs/legion/0.3.0/legion/trait.EntityStore.html) vs [legion::world::EntityStory](https://docs.rs/legion/0.3.0/legion/world/trait.EntityStore.html) - the link to `SubWorld` on the first one is broken but works on the second one.

Note that there are probably more cases (e.g. link to SoA on the main page) but it seems cargo-deadlinks doesn't always find them all, the output changes on each run. I reported it as https://github.com/deadlinks/cargo-deadlinks/issues/56.

I don't know how to fix this until https://github.com/rust-lang/rust/issues/43466 is merged.