The ornamental design for a scooter, as shown and described.
FIG. 1 is a perspective view from above, to the front and to the left side of the new design for a scooter;
FIG. 2 is a perspective view from below, to the rear and to the right side thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a left side view thereof;
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom plan view thereof.
In the drawings, the broken lines are for the purpose of illustrating portions of the article that form no part of the claimed design. The dash-dot broken lines represent the bounds of the claim which form no part of the claimed design.