I claim the ornamental design for a flashlight, as shown and described.
FIG. 1 is a perspective view of a flashlight, showing my new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a left side elevational view thereof;
FIG. 5 is a right side elevational view thereof;
FIG. 6 is a top plan view thereof; and
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a perspective view showing the claimed design in an open position. The broken line showing of the handle is included for the purpose of illustrating the claimed design and forms no part of the claimed design.