Clarify docs for all nested options

[colinrotherham]

I noticed last week that we sometimes "dot-prefix" nested option names with the associated parent or component

The Prototype Kit team are looking into generating documentation from component macro-options.json so this change copies what we did for Radios and Checkboxes conditional to structure all nested options correctly

Accordion

1. heading.text, heading.html → heading
2. summary.text, summary.html → summary
3. content.text, content.html → content

Summary list

1. key.text, key.html → key
2. value.text, value.html → value
3. actions.text, actions.html → actions

Like other nested options, these now show as separate tables (with links) on the Design System website:

[colinrotherham]

Related to:

• Produce a 'style guide' for how Nunjucks documentation is written  #3913

[colinrotherham]

We may still want to bring back "dot-prefix" nested object names for readability:

• [SPIKE] Add parent prefixes to nested component options govuk-design-system#2892

[36degrees]

Raised a few suggestions, mainly to try and avoid having multiple 'If x is set' in the same description.

Noticed we're using multiple words to describe when an option is set ('set', 'provided', 'supplied'…) – standardised on 'provided' for now just so we're at least consistent when describing a single option.

Have also added a card to the Trello board to try and address more fully: https://trello.com/c/HvWJ2GMc/20-we-talk-about-options-being-set-provided-supplied-specified-sometimes-within-the-same-description

[colinrotherham]

Rebased with latest main

[romaricpascal]

Looking good, thanks for tidying those up 🙌🏻 @claireashworth do you want to have a quick look maybe before we merge this in as it's mostly content related? 😊

[colinrotherham]

Thanks @romaricpascal

@claireashworth I've pulled together the same "format" used in both #3878 and #3902

description: If `html` is set, this is not required. The ${child} of each ${parent}. ${description}. If `html` is provided, the `text` option will be ignored.

It's wordy, repetitive, but what we use the most at the moment

We should do a follow up once the Design System Nunjucks docs issues Trello board has been reviewed