The ornamental design for a bindingtool, as shown and described.
FIG. 1 is a perspective view of the front, top and left side of a binding tool showing my new design;
FIG. 2 is a perspective view of the rear, top and right side 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;
FIG. 7 is a top view thereof; and,
FIG. 8 is a bottom view thereof.
The broken line showing of the binding tool is included for the purpose of illustrating portions of the binding tool and forms no part of the claimed design.