The ornamental design for a faucet, as shown and described.
FIG. 1 is a front perspective view of a faucet showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The broken lines immediately adjacent to the photographic area at its bottom edge and its spout opening define the bounds of the claimed design and form no part thereof.