The ornamental design for a shirt, as shown and described.
FIG. 1 is a front right-side perspective view of a shirt showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a front left-side perspective view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a rear left-side perspective view thereof;
FIG. 6 is a rear view thereof;
FIG. 7 is a rear right-side perspective view thereof; and,
FIG. 8 is a right side view thereof.
The broken lines on the sides of the shirt extending to the collar represent seams which form no part of the claimed design. The broken lines showing the zipper form no part of the claimed design. The unshaded broken line stripes on the sleeves form no part of the claimed design. The broken lines near the sleeve ends, the neck, and the mid-torso define the bounds of the claimed design and form no part thereof. The broken lines depicting the remainder of the shirt show features that form no part of the claimed design.