The ornamental design for an edging, as shown and described.
FIG. 1 is a perspective view of an edging, according to my new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a left side elevation view thereof;
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
Throughout the Figures, where shown: The broken lines in the drawings depict environmental subject matter only and form no part of the claimed design. The dash-dot-dash lines depict boundaries of the claim and form no part thereof. The edging is shown with a symbolic break in its length drawn in double zigzag lines. Any portion of the article between the break lines forms no part of the claimed design.