[display] hover on Map constructor call

Not sure I've seen this many compiler internals exposed in a single hover yet. :D


- `_new` instead of `new`
- `_Map` (this is #5627 I guess)
- `_Impl_`
- monomorphs (also expected here I guess)

```haxe
class Main {
static function main() {
var map = new Map();
}
}
```