Error when working with embedded crates

[wez]

$ git clone --depth=1 https://github.com/nrf-rs/nrf52.git
$ cd nrf52/nrf52-hal
$ cargo doc
$ cargo docserver

then click the link -> 404

This fails to find the docs presumably because it doesn't know to look at https://github.com/nrf-rs/nrf52/blob/master/.cargo/config#L11 to resolve the correct dir for the docs