The ornamental design for footless kneehigh sock with trim, as shown.
FIG. 1 is a front view of the footless kneehigh sock with trim of the present invention; and,
FIG. 2 is a side view thereof.
The broken lines on the sock represent stitching and form a part of the claimed design. The additional broken lines in the views are directed to environment and form no part of the claimed design.