update allowance column (#322)

* update allowance column

update role descendant allowances.
update “kind of content” column to reflect HTML kind of content categories for elements with implict matching roles.  These do not always have a 1-to-1 match as there are variants in what ARIA might allow vs the native HTML element.  Additionally, content model categories like sectioning root, or labelable elements, etc. were purposfully left off as the ARIA roles do not automatically come with the features associated with these categories.

* update placeholder link in changelog

* additional wording updates

add informative label to this section.
revise wording to remove normative "must not" since we need this section to be informative at this time.

provide additional wording regarding the roles that indicate to review the 'Required Owned Elements' as specified in ARIA

* fix typo on column number