The ornamental design for a watchcase, as shown and described.
FIG. 1 is a front elevational view of a watch case showing our new design;
FIG. 2 is a rear elevational view thereof;
FIG. 3 is a right side elevational view thereof;
FIG. 4 is a left side elevational view thereof;
FIG. 5 is a top plan view thereof;
FIG. 6 is a bottom plan view thereof; and,
FIG. 7 is a right front perspective view thereof.
The structural features depicted by broken lines in FIG. 2 have been shown for the purpose of illustrating portions of the watch case that form no part of the claimed design.