The ornamental design of a showerhead, as shown and described.
FIG. 1 is a perspective view of a showerhead according to the present invention.
FIG. 2 is a left side elevational view of the showerhead of FIG. 1, the front, rear and right side elevational views of the showerhead being identical thereto.
FIG. 3 is a top plan view of the showerhead of FIG. 1; and,
FIG. 4 is a bottom plan view of the showerhead of FIG. 1.
The dashed lines illustrate environment that does not form a part of the present invention, and no claim is made to the material illustrated with dashed lines.