The ornamental design for a hat, as shown and described.
FIG. 1 is a front perspective view of the hat;
FIG. 2 is another front perspective view of the hat;
FIG. 3 is a left side elevation view of the hat, the right side elevation view being a mirror image thereof;
FIG. 4 is a front elevation view of the hat; the rear elevation view being a mirror image thereof; and,
FIG. 5 is a plan view of the hat from above.
The hat is characterized by a distinctive crown. In FIGS. 1-5, the broken lines showing the brim of the hat or other aspects are for the purpose of illustrating environmental structure only and form no part of the claimed design.