The ornamental design for a hat, as shown and described.
FIG. 1 is a front perspective view of a hat;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a first side view thereof;
FIG. 5 is a second side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof; and,
FIG. 8 is an exemplary view of a user wearing the hat.
The broken lines along the brim of the hat depict portions of the hat that form no part of the claimed design. The broken line depiction of the partial human figure in FIG. 8 illustrates the hat in a position of use and forms no part of the claimed design.