I am not sure if I understand well what you are asking for. You want something to tell you, as a reminder to yourself, that you have actually performed a reboot after an update which requires one? Because reboot doesn’t “happen” by themselves. You have to perform them yourself.
The following may not be what you are asking for but will let you know beform you perform an update if a reboot is necessary not. You can make running it part of your update routine.