The ornamental design for a cap, as shown and described.
FIG. 1 is a front perspective view of a cap according to a first embodiment of the design;
FIG. 2 is a rear perspective view thereof;
FIG. 3 is a right side view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a top view thereof;
FIG. 6 is a bottom view thereof;
FIG. 7 is a front perspective view of a cap according to a second embodiment of the design;
FIG. 8 is a rear perspective view thereof;
FIG. 9 is a right side view thereof;
FIG. 10 is a left side view thereof;
FIG. 11 is a top view thereof; and,
FIG. 12 is a bottom view thereof.
The portions of the cap shown in broken lines in FIGS. 1-12 do not form part of the claimed design. The dot shading shown in FIGS. 6 and 12 illustrates a liner on the concave inner surface of the cap only and does not illustrate any particular color, material, texture, pattern, or finish of liner.