feat(v5): Update Accordion

[kyletsang]

https://v5.getbootstrap.com/docs/5.0/components/accordion/

Accordion is now its own dedicated component in v5.

Note: I left the examples for the custom-toggle card-based components just because it's still possible to create them. Might be useful down the line?

Changes:

• Rewrite component to match new upstream Accordion component
• Combine AccordionContext and SelectableContext together to simplify and remove null SelectableContext context fix
• Update docs
• Update tests

[jquense]

awesome, gonna try and get some time to take a good look at this. Ping me if i forget!

[kyletsang]

Hey @jquense, are you avail to review some of these existing v5 PRs? I got some free time next week, so I can finish up adding the new beta changes once the existing PRs are merged in.

Thanks!

[jquense]

looks great, small nit and API thoughts

[kyletsang]

New changes:

• Renamed AccordionToggle to AccordionButton
• Reduced the markup required for the accordion by combining AccordionHeader with AccordionButton and AccordionBody with AccordionCollapse
• Removed the need to specify matching eventKeys in the header and body. Now it's passed through AccordionItem using a context, so you only need to declare it once.

<Accordion defaultActiveKey="0">
  <Accordion.Item eventKey="0">
    <Accordion.Header>Accordion Item #1</Accordion.Header>
    <Accordion.Body>Body</Accordion.Body>
  </Accordion.Item>
  <Accordion.Item eventKey="1">
    <Accordion.Header>Accordion Item #2</Accordion.Header>
    <Accordion.Body>Body</Accordion.Body>
  </Accordion.Item>
</Accordion>

[jquense]

awesome. We've also come full circle to rebuilding the 5 year old Accordion component API from like bootstrap v3