1.4.0: documentation cannot be build using latest sphinx

### Describe the bug

Looks like documentation cannot be build usog latest sphinx 6.1.3.

### To Reproduce

Just run `sphinx-build -n -T -b html docs` in source tree.

### Expected behavior

It should be possible to build documentation.

### Logs/tracebacks

```python-traceback
+ /usr/bin/sphinx-build -n -T -b man docs build/sphinx/man
Running Sphinx v6.1.3
making output directory... done
loading intersphinx inventory from http://docs.python.org/3/objects.inv...
loading intersphinx inventory from http://docs.sqlalchemy.org/en/latest/objects.inv...
loading intersphinx inventory from http://initd.org/psycopg/docs/objects.inv...
intersphinx inventory has moved: http://docs.python.org/3/objects.inv -> https://docs.python.org/3/objects.inv
intersphinx inventory has moved: http://docs.sqlalchemy.org/en/latest/objects.inv -> https://docs.sqlalchemy.org/en/20/objects.inv
WARNING: failed to reach any of the inventories with the following issues:
intersphinx inventory 'http://initd.org/psycopg/docs/objects.inv' not fetchable due to : HTTPConnectionPool(host='initd.org', port=80): Max retries exceeded with url: /psycopg/docs/objects.inv (Caused by NewConnectionError(': Failed to establish a new connection: [Errno 110] Connection timed out'))
building [mo]: targets for 0 po files that are out of date
writing output...
building [man]: all manpages
updating environment: [new config] 11 added, 0 changed, 0 removed
reading sources... [ 9%] changes
reading sources... [ 18%] contributing
reading sources... [ 27%] core

Traceback (most recent call last):
File "/usr/lib/python3.8/site-packages/sphinx/cmd/build.py", line 284, in build_main
app.build(args.force_all, args.filenames)
File "/usr/lib/python3.8/site-packages/sphinx/application.py", line 347, in build
self.builder.build_update()
File "/usr/lib/python3.8/site-packages/sphinx/builders/__init__.py", line 308, in build_update
self.build(['__all__'], to_build)
File "/usr/lib/python3.8/site-packages/sphinx/builders/__init__.py", line 327, in build
updated_docnames = set(self.read())
File "/usr/lib/python3.8/site-packages/sphinx/builders/__init__.py", line 434, in read
self._read_serial(docnames)
File "/usr/lib/python3.8/site-packages/sphinx/builders/__init__.py", line 455, in _read_serial
self.read_doc(docname)
File "/usr/lib/python3.8/site-packages/sphinx/builders/__init__.py", line 511, in read_doc
publisher.publish()
File "/usr/lib/python3.8/site-packages/docutils/core.py", line 224, in publish
self.document = self.reader.read(self.source, self.parser,
File "/usr/lib/python3.8/site-packages/sphinx/io.py", line 105, in read
self.parse()
File "/usr/lib/python3.8/site-packages/docutils/readers/__init__.py", line 76, in parse
self.parser.parse(self.input, document)
File "/usr/lib/python3.8/site-packages/sphinx/parsers.py", line 80, in parse
self.statemachine.run(inputlines, document, inliner=self.inliner)
File "/usr/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 169, in run
results = StateMachineWS.run(self, input_lines, input_offset,
File "/usr/lib/python3.8/site-packages/docutils/statemachine.py", line 233, in run
context, next_state, result = self.check_line(
File "/usr/lib/python3.8/site-packages/docutils/statemachine.py", line 445, in check_line
return method(match, context, next_state)
File "/usr/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 3024, in text
self.section(title.lstrip(), source, style, lineno + 1, messages)
File "/usr/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 325, in section
self.new_subsection(title, lineno, messages)
File "/usr/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 391, in new_subsection
newabsoffset = self.nested_parse(
File "/usr/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 279, in nested_parse
state_machine.run(block, input_offset, memo=self.memo,
File "/usr/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 195, in run
results = StateMachineWS.run(self, input_lines, input_offset)
File "/usr/lib/python3.8/site-packages/docutils/statemachine.py", line 233, in run
context, next_state, result = self.check_line(
File "/usr/lib/python3.8/site-packages/docutils/statemachine.py", line 445, in check_line
return method(match, context, next_state)
File "/usr/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 2785, in underline
self.section(title, source, style, lineno - 1, messages)
File "/usr/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 325, in section
self.new_subsection(title, lineno, messages)
File "/usr/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 391, in new_subsection
newabsoffset = self.nested_parse(
File "/usr/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 279, in nested_parse
state_machine.run(block, input_offset, memo=self.memo,
File "/usr/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 195, in run
results = StateMachineWS.run(self, input_lines, input_offset)
File "/usr/lib/python3.8/site-packages/docutils/statemachine.py", line 233, in run
context, next_state, result = self.check_line(
File "/usr/lib/python3.8/site-packages/docutils/statemachine.py", line 445, in check_line
return method(match, context, next_state)
File "/usr/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 2355, in explicit_markup
nodelist, blank_finish = self.explicit_construct(match)
File "/usr/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 2367, in explicit_construct
return method(self, expmatch)
File "/usr/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 2104, in directive
return self.run_directive(
File "/usr/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 2154, in run_directive
result = directive_instance.run()
File "/usr/lib/python3.8/site-packages/sphinx/domains/__init__.py", line 286, in run
return super().run()
File "/usr/lib/python3.8/site-packages/sphinxcontrib/asyncio.py", line 54, in run
return super(PyCoroutineFunction, self).run()
File "/usr/lib/python3.8/site-packages/sphinx/directives/__init__.py", line 236, in run
name = self.handle_signature(sig, signode)
File "/usr/lib/python3.8/site-packages/sphinx/domains/python.py", line 540, in handle_signature
raise TypeError(
TypeError: Python directive method get_signature_prefix() must return a list of nodes. Return value was 'coroutine async-with '.

Exception occurred:
File "/usr/lib/python3.8/site-packages/sphinx/domains/python.py", line 540, in handle_signature
raise TypeError(
TypeError: Python directive method get_signature_prefix() must return a list of nodes. Return value was 'coroutine async-with '.
The full traceback has been saved in /tmp/sphinx-err-hjxukizs.log, if you want to report the issue to the developers.
Please also report this if it was a user error, so that a better error message can be provided next time.
A bug report can be filed in the tracker at . Thanks!
```

### Python Version

```console
$ python --version
3.8.16
```

### aiopg Version

```console
N/A
```

### OS

Lixux x86/64

### Additional context

N/A

### Code of Conduct

- [X] I agree to follow the aio-libs Code of Conduct