[display] hover reports type parameters as classes

This type parameter is printed as a `class` because Haxe reports `item.args.kind` as `DisplayModuleTypeKind.Class`.


```haxe
class Main {
static function main() {}
}
```

It would be more fitting `DisplayItemKind.TypeParameter` instead of `Type`, which would solve this. Hover probably doesn't use that because it was added relatively late.