We claim the ornamental design for a cutting insert, as shown and described.
FIG. 1 is an isometric view from above of a cutting insert showing our new design;
FIG. 2 is a top view of the cutting insert of FIG. 1;
FIG. 3 is a bottom view of the cutting insert of FIG. 1;
FIG. 4 is an end elevational view of the cutting insert of FIG. 1, the opposite end elevational view being identical; and,
FIG. 5 is a side elevational view of the cutting insert of FIG. 1, the opposite side elevational view being identical.
The broken line showings of FIGS. 1-5 are included for the purposes of illustrating portions of the cutting insert and form no part of the claimed design.