The ornamental design for a lightfixture, as shown and described.
FIG. 1 is a perspective view of the light fixture showing my new design;
FIG. 2 is a right side elevational view thereof, the left side elevational view being a mirror image;
FIG. 3 a front elevational view thereof, the rear elevational view being a mirror image;
FIG. 4 is a top plan view thereof; and,
FIG. 5 is a bottom plan view thereof.
The areas between the break lines in FIGS. 1-3 form no part of the claimed design. The broken line disclosure represents portions of the fixture which forms no part of the claimed design.