The ornamental design for a lightingfixture, as shown and described.
FIG. 1 is a front elevation view of a new lighting fixture;
FIG. 2 is a back elevation view thereof;
FIG. 3 is a left elevation view thereof.
FIG. 4 is a right elevational view thereof;
FIG. 5 is a top plan view thereof;
FIG. 6 is a bottom plan view thereof;
FIG. 7 is a top perspective view thereof; and,
FIG. 8 is a bottom perspective view thereof.
The horizontal broken line adjacent the ceiling mount, and the power cord in the center of the fixture, both represent environment that forms no part of the claimed design. The broken-line circle on the top surface of the lighting fixture in FIGS. 5 and 7 is intended to demonstrate that no portion of this surface forms part of the claimed design.