minor revisions to deletion and insertion descriptors

Related to [HTML AAM issue 416](w3c/html-aam#416)

Previously the WG thought it reasonable to revise HTML's `<s>` element to map to the `deletion` role, allowing the opportunity to better expose content that is no longer relevant.   This PR is contingent on the merging of the HTML AAM PR to resolve the above linked issue (HTML AAM PR will be linked to via reference to this issue, once submitted).

index.html

@@ -2928,7 +2928,7 @@ <h2>Definition of Roles</h2>
 		<div class="role" id="deletion">
 			<rdef>deletion</rdef>
 			<div class="role-description">
-				<p>A deletion contains content that is marked as removed or content that is being suggested for removal. See related <rref>insertion</rref>.</p>
+				<p>A deletion represents content that is marked as removed, content that is being suggested for removal, or content that is no longer relevant in the context of its accompanying content. See related <rref>insertion</rref>.</p>
 				<p>Deletions are typically used to either mark differences between two versions of content or to designate content suggested for removal in scenarios where multiple people are revising content.</p>
 			</div>
 			<table class="role-features">
@@ -2954,7 +2954,12 @@ <h2>Definition of Roles</h2>
 					</tr>
 					<tr>
 						<th class="role-related-head" scope="row">Related Concepts:</th>
-						<td class="role-related"><code>&lt;del&gt;</code> in [[HTML]]</td>
+						<td class="role-related">
+							<ul>
+								<li><code>&lt;del&gt;</code> in [[HTML]]</li>
+								<li><code>&lt;s&gt;</code> in [[HTML]]</li>
+							</ul>
+						</td>
 					</tr>
 					<tr>
 						<th class="role-scope-head" scope="row">Required Context Role:</th>
@@ -4253,7 +4258,9 @@ <h2>Definition of Roles</h2>
 					</tr>
 					<tr>
 						<th class="role-related-head" scope="row">Related Concepts:</th>
-						<td class="role-related"><code>&lt;ins&gt;</code> in [[HTML]]</td>
+						<td class="role-related">
+							<code>&lt;ins&gt;</code> in [[HTML]]
+						</td>
 					</tr>
 					<tr>
 						<th class="role-scope-head" scope="row">Required Context Role:</th>