The ornamental design for a hat, as shown and described.
FIG. 1 is a front view of a hat showing my new design;
FIG. 2 is a rear view of the hat;
FIG. 3 is a right side view of the hat;
FIG. 4 is a left side view of the hat;
FIG. 5 is a top view of the hat;
FIG. 6 is a bottom view of the hat; and,
FIG. 7 is a top front side perspective view of the hat.
The short dashed broken lines along the gore panels of the hat depict claimed stitching. The long dashed broken line outline of the hat opening and fastener depict portions of the hat that form no part of the claimed design.