The ornamental design for a faucet, as shown and described.
FIG. 1 is a front and left side elevational view of a faucet showing my new design, the front and right side elevational view thereof being a mirror image of the view shown;
FIG. 2 is a left side elevational view thereof shown when the head of the faucet has been extended for use, the right side elevational view thereof being a mirror image of the side view shown;
FIG. 3 is a left side and front enlarged view of the head portion thereof; and,