Documentation: Write up all accessibility documentation

[htmlandbacon]

What

Following Accessiblity example content #582 we need to generate the content to match our internal page template.

Why

so we have consistent accessiblity documentation to take foward.

Done when

• [ ] Hint text
• [ ] Internal service footer
• [ ] Internal service header
• [ ] Key details bar
• [ ] Side navigation
• [ ] Timeline

If we can we should also generate them for our future components

• [ ] Header navigation
• [ ] Primary (In page navigation?)
• [ ] Language Toggle

We should also review our patterns, and see if any guidance makes sense as an example manage a session timeout, is a response how we pass certain WCAG critria

• [ ] Add another thing
• [ ] Choose alternative contact formats
• [ ] Contact a service
• [ ] Find an address
• [ ] Make a declaration
• [ ] Manage a session timeout
• [ ] Toggle to Welsh

Outcomes

We will have clear documentation for all the patterns/components, and a set format for dealing with WCAG documents

Anything else

Depending when we do this we may want to split out tasks