The ornamental design for a fenceornament, as shown and described.
FIG. 1 is a front perspective view of a fence ornament of the present invention.
FIG. 2 is a rear elevation view.
FIG. 3 is a right side elevation view, the left side elevation view being a mirror image thereof.
FIG. 4 is top plan view, the bottom plan view being identical thereto; and,
FIG. 5 is a front elevation view of the fence ornament installed between the horizontal rails and vertical pickets of a fence. The broken lines are for illustrative purposes and form no part of the claimed design.