What is claimed is the ornamental design for a shirt, as shown and described.
FIG. 1 is a front perspective view of a shirt showing our new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a right-side elevational view thereof;
FIG. 5 is a left-side elevational view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines shown (including the football helmets, the sports logos, and the word “Steelers”) in FIGS. 1-7 constitute unclaimed environmental subject matter, which forms no part of the claimed design.