docs(accordion): updated accordion and accordion-item docs for accessibility (#5592)

* docs(accordion): updated accordion docs for accessbility

* docs(accordion): updated accordion-item docs for accessbility

* docs(accordion): fixed link to accordion item

* docs(accordion): fixed link to accordion

* docs(accordion): fixed link to accordion item

* docs(accordion): revised wording for events section

* docs(accordion): link needed the trailing slash

* docs(accordion): link needed the trailing slash

* docs(accordion): changes lang

Author: nikkimk