`NoConfusingPrefixOperator` should report prefix operators with no applied arguments 

`NoConfusingPrefixOperator` seems to only report if the function has at least one argument applied to it.  For example, this is currently not flagged by `NoConfusingPrefixOperator`, and it (presumably?) should be:

```elm
Maybe.map2 (>)
    (Dict.get n outerUses)
    (Dict.get n innerUses)
```

but e.g. this is:
```elm
Maybe.map ((>) 1)
    (Dict.get n innerUses)
```