Fix sphinx warnings

[jhrdt]

Hi,

This PR is a fix for #358 .

Sphinx output:

make -C docs/ html
make[1]: Entering directory '/tmp/conu-fork/docs'
Running Sphinx v2.2.0
making output directory... done
building [mo]: targets for 0 po files that are out of date
building [html]: targets for 25 source files that are out of date
updating environment: [new config] 25 added, 0 changed, 0 removed
reading sources... [  4%] asciinema
reading sources... [  8%] examples
reading sources... [ 12%] index
reading sources... [ 16%] installation
reading sources... [ 20%] new_releases
reading sources... [ 24%] reference/api_index
reading sources... [ 28%] reference/container
reading sources... [ 32%] reference/docker_container
reading sources... [ 36%] reference/docker_image
reading sources... [ 40%] reference/docker_index
reading sources... [ 44%] reference/filesystem_api
reading sources... [ 48%] reference/fixtures_index
reading sources... [ 52%] reference/helpers_index
reading sources... [ 56%] reference/image
reading sources... [ 60%] reference/index
reading sources... [ 64%] reference/k8s_deployment
reading sources... [ 68%] reference/k8s_index
reading sources... [ 72%] reference/k8s_pod
reading sources... [ 76%] reference/k8s_service
reading sources... [ 80%] reference/metadata
reading sources... [ 84%] reference/origin_index
reading sources... [ 88%] reference/other
reading sources... [ 92%] reference/probe
reading sources... [ 96%] reference/util_filesystem
reading sources... [100%] reference/util_index

looking for now-outdated files... none found
pickling environment... done
checking consistency... done
preparing documents... done
writing output... [  4%] asciinema
writing output... [  8%] examples
writing output... [ 12%] index
writing output... [ 16%] installation
writing output... [ 20%] new_releases
writing output... [ 24%] reference/api_index
writing output... [ 28%] reference/container
writing output... [ 32%] reference/docker_container
writing output... [ 36%] reference/docker_image
writing output... [ 40%] reference/docker_index
writing output... [ 44%] reference/filesystem_api
writing output... [ 48%] reference/fixtures_index
writing output... [ 52%] reference/helpers_index
writing output... [ 56%] reference/image
writing output... [ 60%] reference/index
writing output... [ 64%] reference/k8s_deployment
writing output... [ 68%] reference/k8s_index
writing output... [ 72%] reference/k8s_pod
writing output... [ 76%] reference/k8s_service
writing output... [ 80%] reference/metadata
writing output... [ 84%] reference/origin_index
writing output... [ 88%] reference/other
writing output... [ 92%] reference/probe
writing output... [ 96%] reference/util_filesystem
writing output... [100%] reference/util_index

generating indices...  genindex py-modindexdone
writing additional pages...  searchdone
copying static files... ... done
copying extra files... done
dumping search index in English (code: en)... done
dumping object inventory... done
build succeeded.

The HTML pages are in build/html.
make[1]: Leaving directory '/tmp/conu-fork/docs'

[centos-ci]

Can one of the admins verify this patch?

[rpitonak]

[test]

[rpitonak]

Thank you for your contribution!

[TomasTomecek]

Oh my, this is awesome! I was so furious by those warnings and was lazy to take a closer look. Thank you!