The ornamental design for a plasteringtool, as shown and described.
FIG. 1 is a front perspective view of the plastering tool showing my design.
FIG. 2 is a back perspective view thereof;
FIG. 3 is a front elevation view thereof;
FIG. 4 is a back elevation view thereof;
FIG. 5 is a side elevation view thereof, an opposite side elevation view being a mirror image thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The second set of broken lines in the regularly dashed pattern depict portions of the plastering tool that are not considered part of the claimed design.