3.4.0 borks inheritance diagrams of classes with namedtuple class variables

[eigenbrot]

We have a class that uses a namedtuple as a class variable:

class GreatClass(BaseClass):
  
  CoolVar = namedtuple("CoolVar", ["x", "y"])

  ...

Prior to version 3.4.0 this class rendered fine with a correct inheritance diagram. Since the change from #485 in v3.4.0 building the docs produces the following warning:

/repo/docs/autoapi/module/index.rst:XX: WARNING: module.GreatClass.CoolVar specified for inheritance diagram is not a class or module [docutils]

which is true. I think the issue is that since #485 namedtuples are reported as classes.

FWIW, the rendered docs still look correct, but the warning is breaking our build pipelines. Any advice would be greatly appreciated.