The ornamental design for a shavingbrush, as shown and described.
FIG. 1 is an upper perspective view of the shaving brush showing my new design.
FIG. 2 is a side elevation view thereof, other side elevation views being identical;
FIG. 3 is a top plan view thereof; and,
FIG. 4 is a bottom plan view thereof.
The shaving brush is composed of a plurality of bristles cut to different lengths. The handle portion presented in broken lines is for environmental purposes only and forms no part of the claimed design.