Rust rules documentation issues

[Timmmm]

The documentation for rust_binary says:

For more examples, check out our integration tests.

That link is broken and points to the Buck repo, not Buck 2.

Additionally it doesn't say how to integrate with Cargo. There seems to be some autocargo parameter which isn't documented, and also this rust-project tool which isn't mentioned.

[steveklabnik]

Additionally it doesn't say how to integrate with Cargo.

https://github.com/facebookincubator/reindeer is the current best way to do this, imho.