Docs: document new redirect for Disqus comments
See the general Documentation guidelines http://docs.gitlab.com/ce/development/doc_styleguide.html
What does this MR do?
- Documents Disqus redirects (https://gitlab.com/gitlab-com/gitlab-docs/merge_requests/167)
- Delete
/articles/part from doc style guide (for https://gitlab.com/gitlab-org/gitlab-ce/issues/41138) - Intro to docs directory structure
- Update MR description template
EE-version: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/3976
Edited by Marcia Ramos