The ornamental design for a vent, as shown and described.
FIG. 1 is a front perspective view of a vent showing our new design;
FIG. 2 is a bottom perspective view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a right side view thereof, the left side view being a mirror image thereof;
FIG. 5 is a top side view thereof; and,
FIG. 6 is a bottom view thereof.
The broken line showing of portions of a vent is included for the purpose of illustrating environmental structure and forms no part of the claimed design. --