Ensure that all numbered lists use only 1. and no other numbers.
Also ensure that numbered lists use proper spacing.

- Make sure we have type defined in the frontmatter
- Add troubleshooting sections where absent
- Meaningful intros where absent

Signed-off-by: Vincent Fazio <vfazio@xes-inc.com>

List the supported values for client_auth_method

Signed-off-by: Vincent Fazio <vfazio@xes-inc.com>

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 many admin
docs in /high_availability and /auth (part 1)

Previously, we used brackets to denote the tier badges,
but this made Kramdown, the docs site Markdown renderer,
show many warnings when building the site. This is now
fixed by using parentheses instead of square brackets.

This was caused by [PREMIUM] looking like a link to
Kramdown, which couldn't find a URL there.

See:
- https://gitlab.com/gitlab-com/gitlab-docs/merge_requests/484
- https://gitlab.com/gitlab-org/gitlab-ce/issues/63800

First MR in a series updating all redirected links
in CE documentation to the destination URLs

Add backticks around square brackets, or fix links, as necessary.

Linting rule not enabled for now
because tooling produces false
positives.