Interactions in user guide

[YvanMOJdigital]

make it like: https://guidance.data.gov.uk/publish_and_manage_data/

[MatMoore]

The config file for the above site is here: https://github.com/alphagov/datagovuk-tech-docs/blob/main/config/tech-docs.yml

• I think the most important setting we are missing is multipage_nav.
• We can also enable collapsible_nav - without it the nav will be fully expanded all the time.
• max-toc-heading-level can also be used to limit the number of levels shown

The nav tree should match up with the directory structure.