Most of these are no longer applicable due to the introduction of Wagtail guide, where possible the new guide links are used now
- Re-add missing docs image for extending Draftail
- There is no Guide page (yet) for Inserting videos or images so those links have been removed
- Fix some additional reference issues where the page name and reference were causing issues
* Add a border around the userbar menu in Windows high-contrast mode so it can be identified
* Make sure browser font resizing applies to the userbar
* Switch userbar to initialise a Web Component to avoid styling clashes
* Refactor userbar stylesheets to use the same CSS loading as the rest of the admin
- fix some broken refs that were lost in the migration to markdown files
- use lower_snake_case for all internal refs (most follow this convention)
- release process sub-section in docs should be named release schedule instead
Relates to #8383
* Convert the image tag topic to Markdown
* Convert the permissions usage to Markdown
* Convert the topic of snippets to Markdown
* Convert the streamfield topic to markdown
* Convert the writing templates doc to Markdown
