The ornamental design for a DOT-bullet turn signal, as shown and described.
FIG. 1 is a perspective view of the DOT-bullet turn signal.
FIG. 2 is top plane view of the top plane of the DOT-bullet turn signal.
FIG. 3 is a side plane view of the side end of the DOT-bullet turn signal. Each side plane view of the sides of the DOT-bullet turn signal is identical; and,
FIG. 4 is a bottom plane view of the bottom plane of the DOT-bullet turn signal.