The Supreme Court has ruled 5 to 4 that state workers cannot file employment discrimination suits against their employers under the Americans with Disabilities Act of 1990. The court’s majority held that Congress went beyond its authority when it let state workers file such claims. The case decided yesterday concerns two suits brought against Alabama by employees accusing state agencies of discrimination because of medical problems — breast cancer in the case of Patricia Garrett and respiratory ailments in the case of Milton Ash.