The ornamental design for a cover, as shown and described.
FIG. 1 is a top perspective view of a claimed design;
FIG. 2 is a top perspective view of FIG. 1, shown in a configuration of use;
FIG. 3 is a front view of FIG. 1;
FIG. 4 is a rear view thereof;
FIG. 5 is a right side view thereof, with the left side view being a mirror image;
FIG. 6 is a top view thereof; and,
FIG. 7 is a cross-sectional view taken along and in the direction of line 7-7 in FIG. 6.
The dash-dash broken lines illustrate portions of the cover that form no part of the claimed design. The dash-dot broken lines illustrate the boundaries of the claimed design. The cover is shown with symbolic breaks. The appearance of any portion of the cover between the break lines form no part of the claimed design.