### What it does
Checks for items declared `pub(crate)` that are not crate visible because they
are inside a private module.

### Why is this bad?
Writing `pub(crate)` is misleading when it's redundant due to the parent
module's visibility.

### Example
```
mod internal {
    pub(crate) fn internal_fn() { }
}
```
This function is not visible outside the module and it can be declared with `pub` or
private visibility
```
mod internal {
    pub fn internal_fn() { }
}
```