For wrap hints, use '_' to signify return value
When pass-by-reference is used with pointers, sometimes it is necessary to use the method's return value as a hint for the size
of the array that the pointer points to. Now '_'
can be used to signify that the return value is the size.
This change is needed in order to hint the vtkCell3D
methods that were recently added.
Closes #18666 (closed)
Edited by David Gobbi