The ornamental design for a grill, as shown and described.
FIG. 1 is a front isometric view of the grill of the present invention;
FIG. 2 is a rear isometric view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a right side view thereof; and,
FIG. 7 is a top plan view thereof.
The broken lines inside the four vent openings represent bounds of the claimed design, and the broken line and the region enclosed by the broken lines is not part of the claimed design.