The ornamental design for a watchstrap, as shown and described.
FIG. 1 is a perspective view of a watch strap showing my new design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a right side elevational view thereof;
FIG. 4 is a front elevational view thereof;
FIG. 5 is a rear elevational view thereof; and,
FIG. 6 is a bottom plan view thereof.
The left side elevational view is a mirror image of the right side elevational view illustrated in FIG. 3. The broken-line showing in FIGS. 1–6 are for illustrative purposes only and form no part of the claimed design.