Fix: Missing super().__del__() in Cycles and Hydra render engine

According to the Python API release notes, this is required now along
with super().__init__() which was already done.

Also fixes mistake in example in API docs.

Pull Request: https://projects.blender.org/blender/blender/pulls/132476

doc/python_api/rst/info_overview.rst

@@ -206,7 +206,7 @@ must always be called, otherwise Blender's internal initialization won't happen
 
       def __del__(self):
          ...
-         super.__del__()
+         super().__del__()
 
 .. note::