FIG. 1 is an upper rear left perspective view of a highlighter showing my new design;

FIG. 2 is a right side elevation view thereof;

FIG. 3 is an enlarged top plan view thereof;

FIG. 4 is a front perspective view thereof;

FIG. 5 is a left side elevation view thereof;

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is a rear elevation view thereof.

The broken lines showing portions of the top are included for the purpose of illustrating environment and form no part of the claimed design.