Expand documentation styleguide for docs linting
We should give more details on the various tests being run on documentation, as seen in the docs-lint
job itself:
https://gitlab.com/gitlab-org/gitlab-ce/blob/master/.gitlab/ci/docs.gitlab-ci.yml#L66
This should be added to the testing section in the documentation development documentation:
https://docs.gitlab.com/ee/development/documentation/index.html#testing
Edited by Marcel Amirault