The ornamental design for a lintbrush, as shown and described.
FIG. 1 is a front perspective view of a lint brush showing our new design in a first configuration where the lint brush cap is detached from the lint brush bristles;
FIG. 2 is a front perspective view of the lint brush in second configuration where the lint brush cap is attached to the lint brush bristles;
FIG. 3 is a front elevation view thereof;
FIG. 4 is a rear elevation view thereof;
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a left side elevation view thereof;
FIG. 7 is the top plan view thereof; and,
FIG. 8 is the bottom plan view thereof.
The broken lines in the drawings depict portions of the lint brush that form no part of the claimed design. In particular, the lint brush bristles form no part of the claimed design.