The ornamental design for the endoscope, as shown and described.
FIG. 1 is a perspective view of an endoscope showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a top plan view thereof;
FIG. 5 is a bottom view thereof;
FIG. 6 is a left side view thereof;
FIG. 7 is a right side view thereof; and,
FIG. 8 is a front view thereof, shown in an in-use state.
The imaginary line created by drawing a straight line from the end points of the solid lines that are adjacent to the dot-dash broken lines is the boundary 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.