The ornamental design for a cap, as shown and described.
FIG. 1 is a front perspective view from top and right side of a cap, shown in a closed position;
FIG. 2 is a front view thereof;
FIG. 3 is a top view thereof;
FIG. 4 is a bottom view thereof;
FIG. 5 is a left side back view thereof;
FIG. 6 is a right side back view thereof; and,
FIG. 7 is a front perspective view from the top and right side of the cap of FIG. 1, shown in an open position.
Any portion of the article depicted in broken lines forms no part of the claimed design. Broken lines formed by equal length dashes show unclaimed subject matter.