SPRINGFIELD — The state’s high court today unplugged an appeal over higher electricity rates aimed at funding the world’s first “clean coal” power plant.Illinois’ top justices in an opinion released this morning ruled the issue was moot after the federal government last year ceased funding the FutureGen 2.0 power plant in downstate Meredosia.A trade association representing power companies had challenged an Illinois Commerce Commission decision that would have forced the state’s …