The ornamental design for a shower handle, as shown and described.
FIG. 1 is a front perspective view of a shower handle showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The broken line adjacent to the shaded region located near the midpoint of the handle stem represents in unclaimed boundary of the design. The broken line showing of the remainder of the faucet represents unclaimed areas and forms no part of the claimed design.