The ornamental design for a handmuff, as shown and described.
FIG. 1 is a perspective view taken from the front, left side and top side of the hand muff of the present design, shown attached to a stroller, in accordance with the present design.
FIG. 2 is a top plan view of the hand muff of FIG. 1.
FIG. 3 is a bottom plan view of the hand muff of FIG. 1.
FIG. 4 is a front elevation view of the hand muff of FIG. 1.
FIG. 5 is a rear elevation view of the hand muff of FIG. 1.
FIG. 6 is a left side elevation view of the hand muff of FIG. 1.
FIG. 7 is a right side elevation view of the hand muff of FIG. 1.
FIG. 8 is a top plan view of the hand muff of FIG. 1, shown flat in an open position; and,
FIG. 9 is a bottom plan view of the hand muff of FIG. 1, shown flat in an open position.
Elements drawn in broken short/long dash lines form no part of the claimed design.