The ornamental design for a lightingfixture, as shown and described.
FIG. 1 is a bottom right perspective view of a new lighting fixture design in which the lampshade portion thereof is not shown;
FIG. 2 is a back elevation view thereof;
FIG. 3 is a left side elevation view thereof;
FIG. 4 is a right side elevation view thereof;
FIG. 5 is a top plan view thereof;
FIG. 6 is a bottom plan view thereof;
FIG. 7 is a top right perspective view thereof;
FIG. 8 is a top right perspective view thereof in which the lampshade portion thereof is not shown; and,
FIG. 9 is a bottom right perspective view thereof.
The broken line showing of the wall plate, light bulb and lamp shade portion of the lighting fixture is included for the purpose of illustrating environmental structure only and forms no part of the claimed design.