The ornamental design for a jacket, as shown and described.
1. Jacket
1.1 : Perspective
1.2 : Front
1.3 : Back
1.4 : Left
1.5 : Right
1.6 : Top
1.7 : Bottom
The present design is a jacket that has zippers on both sides of the front; the present design is a partial design and the part represented by the solid line is the part to be registered as a design.