Subclasses of mixed-in classes inherit from only the un-mixed bpy_types superclasses

[Mysteryem]

bpy.types.ShaderNode is mixed with bpy_types.ShaderNode.
bpy_types.ShaderNode is a sub-class of bpy_types.NodeInternal.
bpy_types.NodeInternal is a sub-class of bpy_types.Node.
The issue is that bpy_types.Node gets mixed with bpy.types.Node, so in the generated bpy.types py file we make bpy.types.Node a subclass of bpy_types.Node, but bpy.types.ShaderNode should also inherit from bpy.types.Node and this is currently missing.