Display alternate signatures in autocomplete thanks to Converters

We have various Converters in XWiki that we use in velocity to automatically convert a type to another (e.g. a DocumentReference to/from a String).
It means that we can use in velocity a method that requires a DocumentReference with a String type. It would be useful to find a way to display that information when using autocomplete. Either by displaying alternate signatures, or once inserted by displaying a hint.
This information is useful for both parameters but also for returning type of the methods.