The ornamental design for a flashlight, as shown and described.
1. Flashlight
1.1: Perspective
1.2: Perspective
1.3: Perspective
1.4: Front
1.5: Back
1.6: Left
1.7: Right
1.8: Top
1.9: Bottom
1.10: Enlarged
The evenly broken lines in the reproductions, depict unclaimed portions of the flashlight; The dash-dot broken lines shown in the reproductions, depict the boundary of the enlarged view; the broken lines form no part of the claimed design.