The ornamental design for a hat, as shown and described.
FIG. 1 is a top and side perspective view of a hat;
FIG. 2 is a bottom and side perspective view thereof;
FIG. 3 is a side elevation view thereof, the opposite side being a mirror image thereof;
FIG. 4 is a top plan view thereof;
FIG. 5 is a bottom plan view thereof;
FIG. 6 is a front elevation view thereof; and,
FIG. 7 is a rear elevation view thereof.
The portions of the hat illustrated in long even length broken lines and the unshaded areas within the long even length broken lines adjacent to the solid lines of the hat depict portions of the hat that form no part of the claimed design. The short dashed broken lines in FIGS. 2 and 5 form a boundary to the claimed design and form no part of the claimed design.