I claim the ornamental design for a lighting device, as shown and described.
FIG. 1 is a perspective view of a lighting device showing my new design, as viewed from the top and one side.
FIG. 2 is a hack elevation view of the lighting device of FIG. 1.
FIG. 3 is a first side elevation view of the lighting device of FIG. 1.
FIG. 4 is a top plan view of the lighting device of FIG. 1.
FIG. 5 is a second side elevation view of the lighting device of FIG. 1.
FIG. 6 is a front elevation view of the lighting device of FIG. 1.
FIG. 7 is a bottom plan view of the lighting device of FIG. 1; and,
FIG. 8 is a perspective view of the lighting device of FIG. 1 with the light head tilted and the U-shaped bracket supporting the light head rotated, as viewed from the top and one side.
The details shown in broken lines illustrate portions of the lighting device that form no part of the claimed design.