The ornamental design for a switch, as shown and described.
FIG. 1 is a front side view of a switch showing my new design;
FIG. 2 is a rear side view thereof;
FIG. 3 is a left side view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a top plan view thereof; the bottom plan view is a mirror image thereto;
FIG. 6 is a front left perspective view thereof; and,
FIG. 7 is an enlarged sectional view thereof taken along line 7—7 of FIG. 1.
The broken line in FIGS. 1 through 7 show unclaimed subject matter and unclaimed environmental detail and therefore forms no part of the claimed design.