The ornamental design for a lightfixture, as shown and described.
FIG. 1 is a bottom perspective view of a light fixture in accordance with my design, illustrating a first adjustable position of various portions of the light fixture;
FIG. 2 is a front elevation view of the light fixture in accordance with my design, illustrating a first adjustable position of various portions of the light fixture;
FIG. 3 is a bottom plan view of the light fixture in accordance with my design, illustrating a first adjustable position of various portions of the light fixture; and,
FIG. 4 is a back elevation view of the light fixture in accordance with my design, illustrating a first adjustable position of various portions of the light fixture.
The broken lines showing environmental structure are for illustrative purposes only and form no part of the claimed design.