sphinx_toctree_autodoc_fix fails with `sphinx-click`

[tony]

sphinx-click issue when bulding pages

Error log

Traceback (most recent call last):
  File "/cihai-cli/.venv/lib/python3.10/site-packages/sphinx/events.py", line 94, in emit
    results.append(listener.handler(self.app, *args))
  File "/cihai-cli/.venv/lib/python3.10/site-packages/sphinx_toctree_autodoc_fix.py", line 181, in process_doc
    toc = build_toc(doctree)
  File "/cihai-cli/.venv/lib/python3.10/site-packages/sphinx_toctree_autodoc_fix.py", line 82, in build_toc
    sub_item = build_toc(sectionnode, depth + 1)
  File "/cihai-cli/.venv/lib/python3.10/site-packages/sphinx_toctree_autodoc_fix.py", line 104, in build_toc
    fullname = title.attributes["fullname"]
KeyError: 'fullname'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/cihai-cli/.venv/lib/python3.10/site-packages/sphinx/cmd/build.py", line 277, in build_main
    app.build(args.force_all, filenames)
  File "/cihai-cli/.venv/lib/python3.10/site-packages/sphinx/application.py", line 349, in build
    self.builder.build_update()
  File "/cihai-cli/.venv/lib/python3.10/site-packages/sphinx/builders/__init__.py", line 301, in build_update
    self.build(to_build,
  File "/cihai-cli/.venv/lib/python3.10/site-packages/sphinx/builders/__init__.py", line 317, in build
    updated_docnames = set(self.read())
  File "/cihai-cli/.venv/lib/python3.10/site-packages/sphinx/builders/__init__.py", line 424, in read
    self._read_serial(docnames)
  File "/cihai-cli/.venv/lib/python3.10/site-packages/sphinx/builders/__init__.py", line 445, in _read_serial
    self.read_doc(docname)
  File "/cihai-cli/.venv/lib/python3.10/site-packages/sphinx/builders/__init__.py", line 498, in read_doc
    publisher.publish()
  File "/cihai-cli/.venv/lib/python3.10/site-packages/docutils/core.py", line 219, in publish
    self.apply_transforms()
  File "/cihai-cli/.venv/lib/python3.10/site-packages/docutils/core.py", line 200, in apply_transforms
    self.document.transformer.apply_transforms()
  File "/cihai-cli/.venv/lib/python3.10/site-packages/sphinx/transforms/__init__.py", line 80, in apply_transforms
    super().apply_transforms()
  File "/cihai-cli/.venv/lib/python3.10/site-packages/docutils/transforms/__init__.py", line 171, in apply_transforms
    transform.apply(**kwargs)
  File "/cihai-cli/.venv/lib/python3.10/site-packages/sphinx/transforms/__init__.py", line 381, in apply
    self.app.emit('doctree-read', self.document)
  File "/cihai-cli/.venv/lib/python3.10/site-packages/sphinx/application.py", line 460, in emit
    return self.events.emit(event, *args, allowed_exceptions=allowed_exceptions)
  File "/cihai-cli/.venv/lib/python3.10/site-packages/sphinx/events.py", line 105, in emit
    raise ExtensionError(__("Handler %r for event %r threw an exception") %
sphinx.errors.ExtensionError: Handler <bound method BetterTocTreeCollector.process_doc of <sphinx_toctree_autodoc_fix.BetterTocTreeCollector object at 0x7f2e19aaee90>> for event 'doctree-read' threw an exception (exception: 'fullname')

Extension error (sphinx_toctree_autodoc_fix):
Handler <bound method BetterTocTreeCollector.process_doc of <sphinx_toctree_autodoc_fix.BetterTocTreeCollector object at 0x7f2e19aaee90>> for event 'doctree-read' threw an exception (exception: 'fullname')
Command exited with exit code: 2
The server will continue serving the build folder, but the contents being served are no longer in sync with the documentation sources. Please fix the cause of the error above or press Ctrl+C to stop the server.

Effects: tmux-python/tmuxp#812, cihai/cihai-cli#283