0.8.0: sphinx warnings reference target not found

[kloczek]

On building my packages I'm using sphinx-build command with -n switch which shows warmings about missing references. These are not critical issues.
Here is the output with warnings:

+ /usr/bin/sphinx-build -n -T -b man docs build/sphinx/man
Running Sphinx v4.5.0
making output directory... done
[autosummary] generating autosummary for: api.rst, appendix.rst, changes.rst, development.rst, index.rst, usage.rst
loading intersphinx inventory from https://docs.python.org/3/objects.inv...
loading intersphinx inventory from https://docs.python.org/2/objects.inv...
loading intersphinx inventory from https://docs.python.org/3/objects.inv...
building [mo]: targets for 0 po files that are out of date
building [man]: all manpages
updating environment: [new config] 6 added, 0 changed, 0 removed
reading sources... [100%] usage
looking for now-outdated files... none found
pickling environment... done
checking consistency... done
writing... python-easy-server.3 { usage api development appendix changes } /home/tkloczko/rpmbuild/BUILD/easy-server-0.8.0/easy_server/_vault_file.py:docstring of easy_server.VaultFile.nicknames:3: WARNING: py:class reference target not found: list of string
done
build succeeded, 1 warning.

You can peak on fixes that kind of issues in other projects
latchset/jwcrypto#289
click-contrib/sphinx-click@abc31069
latchset/jwcrypto#289
RDFLib/rdflib-sqlalchemy#95