The ornamental design for a dishrack, as shown and described.
FIG. 1 is a front and top perspective view of a dish rack, showing my new design;
FIG. 2 is a rear and bottom perspective view thereof;
FIG. 3 is a front elevation view thereof;
FIG. 4 is a rear elevation view thereof;
FIG. 5 is a left side elevation view thereof;
FIG. 6 is a right side elevation view thereof;
FIG. 7 is a top plan view thereof;
FIG. 8 is a bottom plan view thereof; and,
FIG. 9 is another perspective view thereof, shown in a using position.
The broken lines in the figures illustrate portions of the dish rack that form no part of the claimed design. The broken lines showing of holders in FIG. 9 depict environmental structure that form no part of the claimed design.