The ornamental design for a sharpeningtool, as shown and described.
FIG. 1 is front perspective view of a sharpening tool showing my new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a right side elevation view thereof;
FIG. 5 is a left side elevation view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a rear elevation view thereof as chucked into an environmental power tool.
The broken line showing of the power tool is provided for the purpose of illustrating environmental structure, of which does not form part of the claimed design.