* Docs: improve/expand button documentation
- since we're not doing the disabled cursor thing anymore anyway, remove confusing/unnecessary mention for link-based disabled buttons
- make the disabled toggle example using a link actually follow the preceding advice of also having `tabindex="-1"` and `aria-disabled="true"`
- tweak the link functionality callout to also still mention `aria-disabled` to reinforce the idea
- tweak toggle state description (not just `<button>`s, but also links etc...so just remove mention of `<button>` there; also reinforce accessibility aspect once more)
- add a new callout that cross-references checkbox-based toggles, and what the similarity/difference between them is
- add a matching cross-reference callout to the checkbox-based toggle buttons page
* Update link to now renamed checks-radios.md
