[FeatureRequest] Raise driver-warning event when reaching speedlimit set in M569.4

[nikscha]

M569.4 will let us configure a speedlimit for closed loop stepper motors opperated in constant torque mode. It would be nice if a driver- warning event is raised when this happens. This would allow us to react to such a condition in the driver-warning macro

[nikscha]

Thinking about it there's plenty of usecases unlike mine that wouldn't benefit from this at all and so many warnings are annoying... Maybe best if this behavior can be toggled on/off?