Clarify required states for input type=radio and checkbox #1109

when an input type=radio has a role=menuitemradio, it shoudn't be required to use aria-checked, as authors can instead leverage the default checked attribute / state of the input.

similarly with input type=checkbox when it has a role=menuitemcheckbox and role=switch.

Finally, an input type=checkbox can have role=button, but only if it is paired with aria-pressed=true