Ensure `Either` type is referenced correctly
Ensure `Either` type is referenced correctly

Crates can be renamed in `Cargo.toml`. To ensure we reference the
`Either` type correctly, we need to use the special-cased `$crate`
substitution.

See https://veykril.github.io/tlborm/decl-macros/minutiae/import-export.html.

bluss/either