The ornamental design for a watchstrap, as shown and described.
1. Watch strap
1.1: Perspective
1.2: Perspective
1.3: Front
1.4: Back
1.5: Left
1.6: Right
1.7: Top
1.8: Bottom
1.9: Enlarged
The parts shown by means of broken lines in the reproductions are not part of the claimed design; fig. 1.9is an enlarged view of a portion labeled “9” in fig. 1.1; The dash dot dash lines in fig. 1.1, fig. 1.9, and the label “9” in fig. 1.1are for the purpose of depicting the cut line of the enlarged view and form no part of the claim.