The ornamental design for a lighter, as shown and described.
FIG. 1 is a first perspective view of a lighter showing my new design;
FIG. 2 is a second perspective view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a back view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a right side view thereof;
FIG. 7 is a top view thereof;
FIG. 8 is a bottom view thereof; and,
FIG. 9 is an enlarged view of the selected portion 9 in FIG. 1.
The broken lines consisting of evenly spaced dash lines in the drawing depict portions of the lighter that form no part of the claimed design; The broken lines consisting of short and long dash lines encircling the enlarged detail views are for annotative purposes that form no part of the claimed design.