Many code blocks are 4spaced, and they render in GitLab
without coloring as a result, even though they are
fenced with a language label. If in a list, other items
will render as being in a code block too, even if not
meant to. This fixes all these issues for most docs in
/ci, and cleans up other minor whitespace issues too.
Fix more links after review
Update redirect_from link
Apply suggestion to doc/ci/introduction/index.md
Apply suggestion to doc/ci/README.md
Apply suggestion to doc/ci/README.md
Make front matter redirect_from links absolute
Change front matter to fix discus comments