The ornamental design for a lightingfixture, as shown and described.
FIG. 1 is a bottom perspective view showing the new design for a lighting fixture;
FIG. 2 is a top perspective view of the lighting fixture of FIG. 1;
FIG. 3 is a right-side view of the lighting fixture of FIG. 1;
FIG. 4 is a left-side view of the lighting fixture of FIG. 1;
FIG. 5 is a top view of the lighting fixture of FIG. 1; and,
FIG. 6 is a bottom view of the lighting fixture of FIG. 1.
The dashed lines showing portions of the lighting fixture are included for the purpose of illustrating environment and form no part of the claimed invention.