Python API documentation updates: a description of class hierarchy

was added to the docstrings of most Python extension types.

source/blender/freestyle/intern/python/Interface0D/CurvePoint/BPy_StrokeVertex.cpp

@@ -13,6 +13,8 @@ extern "C" {
 //------------------------INSTANCE METHODS ----------------------------------
 
 static char StrokeVertex___doc__[] =
+"Class hierarchy: :class:`Interface0D` > :class:`CurvePoint` > :class:`StrokeVertex`\n"
+"\n"
 "Class to define a stroke vertex.\n"
 "\n"
 ".. method:: __init__()\n"