The ornamental design for a vehicletaillight, as shown and described.
FIG. 1 is a front view of a left vehicle taillight, as seen from the rear of a vehicle (the right vehicle taillight being a mirror and is not illustrated);
FIG. 2 is a left side elevational view of the vehicle taillight;
FIG. 3 is a right side elevational view of the vehicle taillight;
FIG. 4 is top plan view of the vehicle taillight;
FIG. 5 is a bottom plan view of the vehicle taillight; and,
FIG. 6 is a rear elevational view of the vehicle taillight.