Lighting Device

FIG. 1 is an isometric view of a top, front, and right side of an ornamental design for a lighting device; FIG. 2 is an isometric view of a bottom, front, and left side of the lighting device of FIG. 1 ; FIG. 3 is a top plan view of the lighting device of FIG. 1 ; FIG. 4 is a bottom plan view of the lighting device of FIG. 1 ; FIG. 5 is a front elevation view of the lighting device of FIG. 1 ; FIG. 6 is a rear elevation view of the lighting device of FIG. 1 ; FIG. 7 is a left elevation view of the lighting device of FIG. 1 ; and, FIG. 8 is a right elevation view of the lighting device of FIG. 1 . The dash-dash-dash broken lines are included for the purpose of illustrating portions of the lighting device that form no part of the claimed design. The part of the photograph shown in a coarser dot pattern within the broken-line perimeter, as well as the broken-line perimeter itself, illustrates portions of the lighting device that form no part of the claimed design.