RemovedInSphinx10Warning: Parser.set_application is deprecated

[woutdenolf]

/usr/local/lib/python3.12/site-packages/sphinx_autodoc_typehints/_parser.py:30: RemovedInSphinx10Warning: 'sphinx_autodoc_typehints._parser._RstSnippetParser.set_application' is deprecated. Check CHANGES for Sphinx API modifications.
  parser.set_application(settings.env.app)

See changelog and the associated merge request. So the call can simply be removed for sphinx>=9.0.