I claim the ornamental design for a lighting fixture, as shown and described.
FIG. 1 is a front elevational view of a lighting fixture. This fixture has mirror image symmetry about a vertical imaginary plane that bisects the canopy. The lantern has three-way, one hundred twenty degree overall rotational symmetry. The lantern glasses, lantern bases, lantern caps, and lantern fasteners each have a circular horizontal cross-section.
FIG. 2 is a top plan view of the lighting fixture of FIG. 1; and,
FIG. 3 is a right side elevational view of the lighting fixture of FIG. 1.