FIG. 1 is a perspective view of a tub spout showing my new design; FIG. 2 is a top plan view thereof; FIG. 3 is a front view thereof; FIG. 4 is a first side view thereof; FIG. 5 is a second side view thereof; and, FIG. 6 is a bottom view thereof. The broken lines showing portions of the faucet spout forms no part of the claimed design.