The ornamental design for a hat, as shown and described.
FIG. 1 is a front, top perspective view of a hat showing my new design;
FIG. 2 is a front, bottom perspective view thereof;
FIG. 3 is a back, perspective view thereof;
FIG. 4 is a left-side view thereof;
FIG. 5 is a right-side view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The broken line outline of the adjustable sting fastener forms no part of the claimed design. The dotted lines along the surface of the hat depict features of the article that form no part of the claimed design.