Added docs on how to debug the derived marco

[qhua948]

No description provided.

[erickt]

Rather than putting argh_derive_expand, what do you think about moving it into examples/example.rs, since we don't have a proper compilable example? cargo expand --example example should still expand the macros.

If we go down this road, can you update https://github.com/google/argh/blob/master/.github/workflows/rust.yml to make sure the example is automatically built?

[qhua948]

Rather than putting argh_derive_expand, what do you think about moving it into examples/example.rs, since we don't have a proper compilable example? cargo expand --example example should still expand the macros.

If we go down this road, can you update https://github.com/google/argh/blob/master/.github/workflows/rust.yml to make sure the example is automatically built?

It did not like very much

 $ cargo expand --example simple_example.rs
error: manifest path `/workspace/argh/Cargo.toml` is a virtual manifest, but this command requires running against an actual package in this workspace

[qhua948]

nvm I figured it out

[erickt]

LGTM. Could you fix the cargo fmt error though?

[qhua948]

Done