Bug #94868 for Math-Geometry-Planar: docs of ->isinside() on boundary points

The docs of ->isinside() don't say whether boundary points are reckoned inside or not. I see from the code that they are. Perhaps expand a little like =head4 $polygon->isinside($point); Returns true if C<$point> is inside the polygon or contour. C<$point> is inside a contour if it is inside the outer polygon and not inside a hole. Points on the boundary are considered inside. Points on the boundary of a hole are considered not inside. (A hole removes the entirety of the hole polygon, including removing its boundary points.)