Confusing help message on an attempt to call a module-local macro

``` rust
mod m {
    macro_rules! k {
        () => ()
    }
}

fn main() {
    k!();
}
```

```
<anon>:8:5: 8:6 error: macro undefined: 'k!'
<anon>:8     k!();
             ^
<anon>:8:5: 8:6 help: did you mean `k!`?
```

The help message is off the point.
- https://play.rust-lang.org/?gist=f707c254c6feded72200&version=nightly
