The ornamental design for a wall-hanging toilet paper holder, as shown and described.
FIG. 1 is a front elevational view of a wall-hanging toilet paper holder
showing my new design, the holder shown as it appears without any toilet
paper rolls being inserted therein;
FIG. 2 is a top, front, and right side perspective view thereof;
FIG. 3 is a right side elevational view thereof, the left side being a
mirror image of that shown;