No completion for second optional argument

```haxe
function main() {
optionalObj({
// no completion
// { } should be Null
// For optional function argument 's'
});
optionalObj({
a: 1,
// no completion
// { a : Int } should be Null
// For optional function argument 's'
});
}

function optionalObj(?s:String, ?o:{a:Int, b:Int}) {}
```
Also would be nice to get `{fields...}`, like with `EitherType`, if this is related to compiler.