The ornamental design for a lightfixture, as shown and described.
FIG. 1 is a top perspective view of a light fixture in accordance with my design;
FIG. 2 is a bottom plan view of the light fixture in accordance with my design;
FIG. 3 is a back elevation view of the light fixture in accordance with my design;
FIG. 4 is a side elevation view of the light fixture in accordance with my design, the opposite view being a mirror image thereof;
FIG. 5 is a front elevation view of the light fixture in accordance with my design; and,
FIG. 6 is a top plan view of the light fixture in accordance with my design.
The broken-line disclosure of portions of the fixture in the views are understood to be for illustrative purposes only and form no part of the claimed design.