Idea: cargo crev expand <crate> [<version>]

[dpc]

We could cargo-expand for allowing reviewing the crate code conveniently without having to cd to a given directory.

We should probably expand build.rs and any other file like this too.

[dpc]

dtolnay/request-for-implementation#6 (comment)

[dtolnay]

Implemented in https://github.com/TedDriggs/syn-inline-mod.

[dpc]

I have implemented a prototype version of this in d5aec67, but it looks like it will lose all the formatting and comments?

> cargo run --release -- crev crate expand -u foo
    Finished release [optimized] target(s) in 0.12s
     Running `target/release/cargo-crev crev crate expand -u foo`
# [cfg (test)] mod tests { # [test] fn it_works () { assert_eq ! (2 + 2 , 4) ; } }
> cat /home/dpc/.cargo/registry/src/github.com-1ecc6299db9ec823/foo-0.0.0/src/lib.rs 
#[cfg(test)]
mod tests {
    #[test]
    fn it_works() {
        assert_eq!(2 + 2, 4);
    }
}