How to limit the maximum output pulse frequency to prevent the user from setting an excessively high pulse rate that could cause grblHAL to crash?

[hanke-cnc]

Some servo users like to set very high pulse rates, which can cause grblHAL to crash. They might think this is a sign of instability. I don't want to keep explaining this to them. I want to take some actions to prevent it from crashing, reduce the user's speed, and issue a warning to them. Anything is fine as long as it doesn't crash.