The ornamental design for a pushswitch, as shown and described.
FIG. 1 is a top, front, and right side perspective view of a push switch showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The broken lines shown in the figures illustrate portions of the push switch that form no part of the claimed design. The unshaded surfaces form no part of the claimed design.