The ornamental design for a switch, as shown and described.
FIG. 1 is a top, front, and right side perspective view of a switch, showing our new design;
FIG. 2 is a bottom, rear, and left side perspective view thereof;
FIG. 3 is a front view thereof,
FIG. 4 is a rear view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a right side view thereof;
FIG. 7 is a top view thereof; and,
FIG. 8 is a bottom view thereof.
The dashed broken lines in the figures show portions of the switch that form no part of the claimed design. The dot-dashed broken lines in the figures represent boundaries and form no part of the claimed design.