The ornamental design for a doll, as shown and described.
FIG. 1 is a perspective view of a doll or portion thereof, showing our new design therefor;
FIG. 2 is a front view thereof;
FIG. 3 is a back view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is right side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof; and,
FIG. 8 is a perspective view of the doll in an alternative broken line disclosure with an exploded view showing layers of alternative broken line eye layers.
The broken lines shown in the figures are for illustrative purposes only and form no part of the claimed design.