By Howard Schneider and Ann Saphir WASHINGTON (Reuters) -The Federal Reserve on Wednesday raised its benchmark overnight interest rate by half a percentage point, the biggest jump in 22 years, and the U.S. central bank’s chief made a direct appeal to Americans struggling with high inflation to hang tough while officials take the hard measures to bring it under control. In a widely expected move, the Fed set its target federal funds rate to a range between 0.75% and 1% in a unanimous decision, with further rises in borrowing costs of perhaps similar magnitude likely to follow. Fed Chair Jerome …