The ornamental design for a lightingfixture, as shown and described.
FIG. 1 is an isometric view of a lighting fixture.
FIG. 2 is another isometric view of the lighting fixture of FIG. 1.
FIG. 3 is a front view of the lighting fixture of FIG. 1.
FIG. 4 is a right side view of the lighting fixture of FIG. 1.
FIG. 5 is a rear view of the lighting fixture of FIG. 1.
FIG. 6 is a left side view of the lighting fixture of FIG. 1.
FIG. 7 is a top view of the lighting fixture of FIG. 1; and,
FIG. 8 is a bottom view of the lighting fixture of FIG. 1.
The dashed broken lines in the drawings denote structure that is not part of the claimed design. The long dash-short dash-long dash lines in the drawings denote unclaimed boundaries of the design.