The ornamental design for a pavingstone, substantially as shown and described.
FIG. 1 is a top perspective view of the paving stone.
FIG. 2 is a top view of the paving stone shown in FIG. 1.
FIG. 3 is a left side view of the paving stone shown in FIG. 1.
FIG. 4 is a rear view of the paving stone shown in FIG. 1.
FIG. 5 is a front view of the paving stone shown in FIG. 1; and,
FIG. 6 is a right side of the paving stone shown in FIG. 1.
The broken lines depict portions of the paving stone that form no part of the claim. In particular, the ribs shown in broken lines on the sides of the paving stone form no part of the claim.