We claim the ornamental design for a showerhead, as shown and described.
FIG. 1 is a bottom, right, front perspective view of an embodiment of the claimed design;
FIG. 2 is a right elevation view thereof;
FIG. 3 is a left elevation view thereof;
FIG. 4 is a front elevation view thereof;
FIG. 5 is rear elevation view thereof;
FIG. 6 is a bottom plan view thereof; and,
FIG. 7 is a top plan view thereof.
The ornamental design which is claimed is shown in solid lines in the drawings. The broken lines in the drawings are for illustrative purposes only and form no part of the claimed design. Broken lines formed by equal length dashes show unclaimed portions of the design. Broken lines formed of unequal length dashes (i.e., dash-dot) show boundaries between claimed and unclaimed portions of the design. Broken lines having a jagged element show that the no particular length of the portion is claimed.