The ornamental design for a sock with fringe, as shown and described.
FIG. 1 is a perspective view of my new sock with fringe design in use;
FIG. 2 is a top view thereof;
FIG. 3 is a bottom view thereof;
FIG. 4 is a side view thereof;
FIG. 5 is a front view thereof; and,
FIG. 6 is a rear view thereof.
The evenly dashed broken lines depict portions of the article and environmental subject matter, and form no part of the claimed design. The dash dot dash broken lines depict the cut line and form no part of the claimed design.