Fix capitalization in docs for works like GitLab, Git
Omnibus, etc

This fixes a regression that does not permit spaces in subgraph titles.

Full details: https://github.com/knsv/mermaid/releases

Deletes extra spaces and line, makes lists consistent, and
fixes links.

Mermaid v8.2.3 added support for styling in subgraphs, but if there are
multiple words in a title, quotes are required.

* https://github.com/knsv/mermaid/pull/845
* https://github.com/knsv/mermaid/issues/391#issuecomment-495602059

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/65338

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

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
woll render as being in a code block too, even if not
meant to. This fixes all these issues, and cleans up
minor whitespace issues in /user, /security, /ssh
and /migrate_ci_to_ce docs.

Search and replace gitlab-com/gitlab-docs with gitlab-org/gitlab-docs.
For https://gitlab.com/gitlab-com/gitlab-docs/issues/310

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

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

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

Adjusts asterisks to hyphens in assorted docs to allow lint rule to pass

Change emoji to Gitlab rendering and fix typo

Use built in renderer for math

Touchups to GFM Doc and bring in suggestions from MR 22122

Fix link

Add epics to align docs

Add epic badge

Fix dashes making accidental headers, and move wikis down, add emoji note

Add section explaining GitLab markdown extensions

Update to incorporate recent changes

Add links rendering, fix issue rendering as color chip

Add links rendering, fix issue rendering as color chip

Update links to GitLab rendered version of markdown doc

Separate GFM extensions, reorder list, other tweaks

Update code blocks and highlighting

Trying to fix improper markdown rendering

Fix rendering broken by triple backticks and add emoji note

testing triple tildes instead of quad backticks

testing rending after mermaid

Various fixes to improve markdown rendering

Update markdown doc after review

Fix markdown doc after review, part two

fix typo in markdown doc

Because the markdown wouldn't have been rendered
on docs.gitlab.com

For the sake of consistency, removes any extraneous
consecutive blank lines from the doc suite.

This engine was replaced with CommonMarker in 11.4, it was deprecated
since then.

In modern Linux distros.

Source: https://www.omgubuntu.co.uk/2018/06/use-emoji-linux-ubuntu-apps

This is a font from [Google](https://www.google.com/get/noto/).

Arch Linux [has a recommendation of it](https://wiki.archlinux.org/index.php/fonts#Emoji_and_symbols).

Add info about this into `docs/user/markdown.md#emoji`