The ornamental design for a tub spout, as shown and described.
FIG. 1 is a front perspective view of a faucet showing my new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a left elevation view thereof;
FIG. 5 is a right elevation view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines immediately adjacent to the photographic area in FIGS. 1, 2, 3, and 7 represent a boundary of the claimed design and form no part thereof. The unshaded regions within the broken line boundary form no part of the claimed design.