The ornamental design for a winch, as shown and described.
FIG. 1 is a perspective view of a winch showing the new design;
FIG. 2 is another perspective view in condition of use;
FIG. 3 is another perspective view thereof;
FIG. 4 is a front view thereof;
FIG. 5 is a rear view thereof;
FIG. 6 is a left side view thereof;
FIG. 7 is a right side view thereof;
FIG. 8 is a top view thereof; and,
FIG. 9 is a bottom view thereof.
The broken lines showing the a clutch wrench for winch depict environmental subject matter only and form no part of the claim, while all other broken lines in the drawings depict portions of the winch that form no part of the claimed design.