The ornamental design for a toolbit, as shown (and described).
FIG. 1 is a perspective view of a tool bit showing my new design;
FIG. 2 is a front elevational view of FIG. 1;
FIG. 3 is a rear elevational view of FIG. 1;
FIG. 4 is a left side view of FIG. 1;
FIG. 5 is a right side view of FIG. 1;
FIG. 6 is a top plan view of FIG. 1; and,
FIG. 7 is a bottom plan view of FIG. 1.
The broken lines in FIGS. 1-7 are for illustrative purposes only and depict portions of the design that form no part of the claim. The surface stippling in FIGS. 1-7 represents a contrast of color, texture, or material.