Is it possible to create tooltips like this for custom GDNative classes and functions?
F.i.: built in classes display a quick function description when writing down a function followed by (

Which is not the case for own classes. Let's say I've got this function in my GDNative Script:
void GDExample::_register_methods() {
register_method("testmethod", &GDExample::testmethod);
}
If I call it in Godot, no help is displayed for it.
custom_class.testmethod(
How can these tooltips be created for custom functions?