The ornamental design for a lightingfixture, as shown and described.
FIG. 1 is a bottom perspective view of a new lighting fixture design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a back elevational view thereof.
FIG. 4 is a right side elevational view thereof;
FIG. 5 is a left side elevational view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a top perspective view thereof.
The broken line disclosure represents portions of the fixture which form no part of the claimed design, and the outermost concentric circle in broken lines visible in FIGS. 1 and 7 represents an unclaimed boundary between claimed and unclaimed portions of the fixture.