- Add a mention od Milestone lists to the terminology section.
- Add links to the Milestone and Assignee lists.
- Style: split long lines.
- Style: add a divider if there's an image followed by a heading.
- Style: don't say "simply".
- Rearrange the Milestone and Assignee lists sections to reflect
  the order in UI.

Closes https://gitlab.com/gitlab-org/gitlab/-/issues/196779