The ornamental design for a catlitterscoop, as shown and described.
FIG. 1 is a left side perspective view of a cat litter scoop showing our new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a back elevational view thereof;
FIG. 4 is a top plan view thereof;
FIG. 5 is a bottom plan view thereof; and,
FIG. 6 is a left side view.
The long/short/long dashed line immediately adjacent to claimed subject matter represents a boundary and the area within the boundary forms no part of the claimed design. The remaining short dashed line represent portions of the cat litter scoop that form no part of the claimed design. None of the broken lines form part of the claimed design.