The ornamental design for a stylus, as shown and described.
FIG. 1 is a perspective view of a stylus showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a top view thereof;
FIG. 4 is a bottom view thereof;
FIG. 5 is an exploded view thereof; and,
FIG. 6 is a perspective view thereof, as shown a stylus environment.
The front view, the rear view, the right side view and the left side view are symmetrically identical. The broken lines in the drawings are included for the purpose of illustration and form no part of the claimed design. The dot-dash lines in the drawings define the boundary of the claim and form no part of the claimed design.