MIDDLETOWN, Ohio (AP) - The city's tax superintendent has been suspended without pay for a week for trying to inject some humor in the city income tax filing instructions. The forms - with such lines as, ""If we can tax it, we will,"" - were sent last week to all Middletown businesses and residents who pay city income tax. The attempt at humor by Linda Stubbs was called ""misguided"" by city Finance Director John Lyons. Lyons said revised forms were sent out immediately at a cost to taxpayers of…