should report unused_import when it reexports nothing

### Code

```Rust
mod a {}

pub use a::*;

fn main() {}
```


### Current output

```Shell
nothing
```


### Desired output

```Shell
unused import: `a::*`
```


### Rationale and extra context

_No response_

### Other cases

_No response_

### Anything else?

_No response_