The ornamental design for a door handle, as shown and described.
FIG. 1 is a perspective view of a door handle showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a back view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof; and,
FIG. 8 is a perspective view of the design shown in FIGS. 1-7, inverted to allow for gripping on an opposite side. The left and right side views being mirror images of FIGS. 4 and 5, and top and bottom views are reversed.
The broken lines in the drawings form no part of the claimed design.