The ornamental design for an endoscope, as shown and described.
FIG. 1 is a front view of the endoscope showing my new design;
FIG. 2 is a rear view of the endoscope shown in FIG. 1;
FIG. 3 is a left side view of the endoscope shown in FIG. 1;
FIG. 4 is a right side view of the endoscope shown in FIG. 1;
FIG. 5 is a bottom view of the endoscope shown in FIG. 1; and,
FIG. 6 is a top view of the endoscope shown in FIG. 1.
The broken lines immediately adjacent the claimed areas represent the bounds of the claimed design while all other broken lines are directed to environment and are for illustrative purposes only; the broken lines form no part of the claimed design.