nextStep method
void
nextStep()
Advances to the next step.
Increments the current step index by 1. Does not validate if the next step exists - callers should check bounds.
Example:
if (controller.value.currentStep < steps.length - 1) {
controller.nextStep();
}
Implementation
void nextStep() {
value = StepperValue(
stepStates: value.stepStates,
currentStep: value.currentStep + 1,
);
}