How to reference types in other crates inside `library!`?

I'm trying to write a `library!` declaration along these lines:

```rust
reflect::library!{
extern crate anyhow {
type Result;
}

extern crate my_crate {
trait MyTrait {
fn trait_fn(&self) -> anyhow::Result;
}
}
}
```

But the macro doesn't seem to support the `anyhow::Result` path. Since the README mentions "There may be additional `extern crate` blocks here if we need to use types from outside the standard library", I'm wondering if I'm missing something or if this is not supported yet. Thanks!