The ornamental design for a shirt, as shown and described.
FIG. 1 is a front perspective view of a shirt showing our new design in an in-use configuration;
FIG. 2 is a front view thereof;
FIG. 3 is a side view thereof;
FIG. 4 is a second side view thereof; and,
FIG. 5 is a top view thereof.
The uneven-length broken lines immediately adjacent to the shaded area represent unclaimed boundaries of the design. The unshaded regions, demarcated by uneven-length broken lines, represent unclaimed portions of the shirt and form no part of the claimed design. The even-length broken lines represent the appearance of stitching. The uneven-length broken lines showing the remainder of the shirt are for environmental purposes only and form no part of the claimed design.