The ornamental design for a lightfixture, as shown and described.
FIG. 1 is is a side elevation view of the light fixture in accordance with my design, all side views being identical;
FIG. 2 is a top plan view of the light fixture in accordance with my design; and,
FIG. 3 is a bottom plan view of the light fixture in accordance with my design.
The broken-line disclosure of elements within the lamp shade structure are understood to represent portions of the article in which the design is embodied, but which form no part of the claimed design.