The ornamental design for a pencilsharpener, as shown and described.
FIG. 1 is a front perspective view of a pencil sharpener;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a side elevation view thereof;
FIG. 4 is an opposite side elevation view thereof;
FIG. 5 is a rear elevation view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines showing features in FIGS. 1, 2, 5, 6, and 7 are included for the purpose of illustrating portions of the pencil sharpener that form no part of the claimed design.