The ornamental design for a pettoilet, as shown and described.
FIG. 1 is a front view of a pet toilet showing my new design;
FIG. 2 is a rear view thereof;
FIG. 3 is a top view thereof;
FIG. 4 is a bottom view thereof;
FIG. 5 is a left-side view thereof, with the right-side view being a mirror image thereof;
FIG. 6 is a front, top and right-side perspective view thereof; and,
FIG. 7 is a front, bottom and right-side perspective view thereof.
The dash-dot-dash broken lines depict the boundary of the claim that form no part of the claimed design. The dash-dash lines depict portions of the pet toilet that form no part of the claimed design