The ornamental design for a horncover, as shown and described.
FIG. 1 is a front perspective view of a horn cover showing our new design.
FIG. 2 is a rear perspective view of FIG. 1.
FIG. 3 is a front elevational view of FIG. 1.
FIG. 4 is a rear elevated view of FIG. 1.
FIG. 5 is a left side elevation view of FIG. 1.
FIG. 6 is a top plan view of FIG. 1.
FIG. 7 is bottom plan view of FIG. 1; and,
FIG. 8 is a right side elevation view of FIG. 1.
No claim is made to the rear portion of the horn cover, or the front central portion, as shown by the use of dashed lines. The portions shown in FIGS. 1-4 in dashed lines, including front and rear portions and perimeter flange openings, are not claimed and are shown for illustration purposes only, and do not contribute a part of the claimed design.