The ornamental design for a coinholder, as shown and described.
FIG. 1 is a front elevational view of a coin holder embodying our design,
the frame seen in dashed lines not forming a part thereof and the shading
showing contrasting colors;
FIG. 2 is a rear elevational view thereof;
FIG. 3 is a top plan view thereof, the bottom plan view being a mirror
image thereof; and,
FIG. 4 is a left side elevational view thereof, the right side elevational
view being a mirror image thereof.