The ornamental design for a clip, as shown and described.
FIG. 1 is a top plan view of a clip showing my new design, the bottom plan view being identical; and,
FIG. 2 is a left side elevational view thereof, the right side elevation view being identical.
The broken lines in the figures illustrate environment only and form no part of the claimed design. The shaded surfaces within the solid-line oval are the only claimed surfaces. The other solid lines are claimed edges only and do not delineate any claimed surfaces.