The ornamental design for an enclosure, as shown and described.
FIG. 1 is a front isometric view of an enclosure in accordance with an embodiment of the invention;
FIG. 2 is a front elevational view of the enclosure of FIG. 1;
FIG. 3 is a back elevational view of the enclosure of FIG. 1;
FIG. 4 is a right side elevational view of the enclosure of FIG. 1;
FIG. 5 is a top plan view of the enclosure of FIG. 1; and,
FIG. 6 is a is a bottom plan view of the enclosure of FIG. 1.
The components shown in dotted lines being for illustrative purposes only and not a part of the claimed design, the left side elevational view (not shown) of the enclosure being a mirror image of the right side elevational view.