The ornamental design for a fastener, as shown and described.
FIG. 1 is a front top perspective view of the present invention.
FIG. 2 is a top plan view of FIG. 1.
FIG. 3 is a bottom plan view of FIG. 1.
FIG. 4 is a left side view of FIG. 1.
FIG. 5 is a right side view of FIG. 1.
FIG. 6 is a front view of FIG. 1.
FIG. 7 is a back view of FIG. 1; and,
FIG. 8 is a perspective view of FIG. 1 shown in use with a pair of wearable suspenders.
The surfaces are lightly lined for contour only. No claim is made to features not shown in the present drawings. The disclaimed portions shown in dot-dot-lining are provided for environmental purposes only and form no part of the claimed design.