include mention of figure/caption (#1704)

* include mention of figure/caption 

this pr updates `aria-details` to mention `figure` and `figcaption`.

This update is related to HTML AAM's update to the `figure` and `figcaption` elements - w3c/html-aam#359. 

It is a follow on to my other PR, #1703 which updates the `caption` role and includes information about `aria-details`.

Co-authored-by: Sarah Higley <smhigley@users.noreply.github.com>

index.html

@@ -11353,6 +11353,7 @@ <h2>Definitions of States and Properties (all aria-* attributes)</h2>
 				<ul>
 					<li>Comment: <code>aria-details</code> refers to an element with role <rref>comment</rref>.</li>
 					<li>Definition: <code>aria-details</code> is applied to an element with role <rref>term</rref> and refers to an element with role <rref>definition</rref>.</li>
+					<li>Caption: <code>aria-details</code> is applied to an element with role <rref>figure</rref> and refers to an element with role <rref>caption</rref>, or an element within a <code>caption</code>.</li>
 					<li>Footnote: <code>aria-details</code> refers to an element with role <code>doc-footnote</code>. This role is defined in [[DPUB-ARIA-1.0]].</li>
 					<li>Endnote: <code>aria-details</code> refers to an element with role <code>doc-endnote</code>. This role is defined in [[DPUB-ARIA-1.0]].</li>
 					<li>Description or general annotation: <code>aria-details</code> refers to an element with any other role.</li>