This changes gives an effect to the default-target option. A crate that adds a default-target to their docs.rs metadata in Cargo.toml will cause docs.rs/my_crate/$VERSION (and docs.rs/my_crate) to redirect to docs.rs/my_crate/$VERSION/$DEFAULT_TARGET/my_crate (assuming a build target of my_crate).

Caveat: the redirect doesn't check that the target has docs available. I'm not sure why but my local clone doesn't properly build and save docs for all targets, so accessing localhost:3000/winapi redirects properly to localhost:3000/winapi/0.3.5/x86_64-pc-windows-msvc/winapi/, but immediately hits a 404. This would work in docs.rs's production environment, but i want to look into adding a check, regardless. whoops that was easier than i thought, all good now. I mean, the bug where it doesn't seem to get the docs for all the targets in a local clone still exists, but at least we don't get bogus redirects now.