The ornamental design for a grill, as shown and described.
FIG. 1 is a front isometric view of the present invention;
FIG. 2 is a detail front isometric view of the invention of FIG. 1; and,
FIG. 3 is a front elevational view of the invention of FIG. 1.
The broken dash lines in the figures represent non-claimed subject matter. Neither the broken dash line portions nor the broken dash lines themselves forms any part of the claimed invention.