The ornamental design for a helmet-mounted light, as shown and described.
FIG. 1 is a front elevational view of the helmet-mounted light;
FIG. 2 is a right-side elevational view thereof;
FIG. 3 is a left-side elevational view thereof;
FIG. 4 is a bottom plan view thereof;
FIG. 5 is a front, bottom perspective view thereof; and,
FIG. 6 is a reference view showing the helmet-mounted light attached to a helmet.
The dot-dash chain line indicates a boundary of the claimed subject matter and forms no part of the claim design. The broken lines depict environmental subject matter only and form no part of the claimed design.