The ornamental design for a faucet, as shown and described.
FIG. 1 is a perspective view of a faucet showing our design;
FIG. 2 is the front elevational view thereof;
FIG. 3 is the rear elevational view thereof;
FIG. 4 is the side elevational view thereof;
FIG. 5 is the top plan view thereof; and,
FIG. 6 is the bottom view thereof.
The broken line disclosures in the view represents portions of the faucet in which the claimed design is embodied, but which forms no part of the claimed design.