The ornamental design for a wrench, as shown and described.
FIG. 1 is a first perspective view of a wrench 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;
FIG. 7 is a bottom view thereof; and,
FIG. 8 is a second perspective view thereof.
The broken line showing of the hardware interface region and the small circular regions is for illustrative purposes only and forms no part of the claimed design.