The ornamental design for a wedge shaped grillbrush, as shown and described.
FIG. 1 is a top isometric view of a wedge shaped grill brush in accordance with the new design;
FIG. 2 is a bottom view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a side view thereof; and,
FIG. 6 is a top view thereof.
The broken lines showing a head in FIG. 1 illustrate the environment in which the article embodying the design is used and all of the other broken lines in the views illustrate portions of the grill brush, none of which form part of the claimed design.