The ornamental design for a spoon, as shown and described.
FIG. 1 is a perspective view of a spoon according to an embodiment of the claimed design.
FIG. 2 is a frontal view of the spoon of FIG. 1.
FIG. 3 is a back view of the spoon of FIG. 1.
FIG. 4 is a top elevation view of the spoon of FIG. 1; and,
FIG. 5 is a right side view of the spoon of FIG. 1.
The left side of the spoon is substantially a mirror image of FIG. 5. The bottom of the spoon is substantially flat and unornamented. Features shown in broken lines are environment only and not part of the claimed design.