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 rear perspective view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a side view thereof;
FIG. 6 is a second side view thereof; and,
FIG. 7 is a top plan view thereof.
The broken lines immediately adjacent to the shaded area represent unclaimed boundaries of the design. The unshaded regions, demarcated by broken lines, represent unclaimed portions of the shirt and form no part of the claimed design. The broken lines showing the remainder of the shirt are for environmental purposes only and form no part of the claimed design.