The ornamental design for the boot, as shown and described.
FIG. 1 is a front elevational view of the boot showing my new design;
FIG. 2 is a rear elevational view thereof;
FIG. 3 is a left side view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a top plan view thereof;
FIG. 6 is a bottom plan view thereof;
FIG. 7 is a perspective view thereof;
FIG. 8 is a second perspective view thereof; and,
FIG. 9 is a third perspective view thereof.
The shoe lace in FIG. 9 shown in broken lines do not form part of the claimed design. All other broken lines shown in the boot are stitches and form part of the claimed design.