Make style containment a part of ''strict'' and ''content'

See #6287

Author: frivoal

css-contain-2/Overview.bs

@@ -142,8 +142,8 @@ Strong Containment: the 'contain' property</h2>
 
 		<dt><dfn>strict</dfn>
 		<dd>
-			This value computes to ''size layout paint'',
-			and thus turns on all forms of <a>containment</a> <em>except</em> <a>style containment</a> for the element.
+			This value computes to ''size layout paint style'',
+			and thus turns on all forms of <a>containment</a> for the element.
 
 			<wpt>
 				contain-strict-001.html
@@ -155,8 +155,8 @@ Strong Containment: the 'contain' property</h2>
 
 		<dt><dfn>content</dfn>
 		<dd>
-			This value computes to ''layout paint'',
-			and thus turns on all forms of <a>containment</a> <em>except</em> <a>size containment</a> and <a>style containment</a> for the element.
+			This value computes to ''layout paint style'',
+			and thus turns on all forms of <a>containment</a> <em>except</em> <a>size containment</a> for the element.
 
 			<wpt>
 				contain-content-001.html
@@ -173,7 +173,7 @@ Strong Containment: the 'contain' property</h2>
 			However, because it doesn't apply <a>size containment</a>,
 			the element can still respond to the size of its contents,
 			which can cause layout-invalidation to percolate further up the tree than desired.
-			Use ''contain: strict'' or ''contain: size layout style paint'' when possible,
+			Use ''contain: strict'' when possible,
 			to gain as much containment as you can.
 
 		<dt><dfn>size</dfn>
@@ -1878,7 +1878,7 @@ This appendix is <em>informative</em>.
 Changes from <a href="https://www.w3.org/TR/2020/WD-css-contain-2-20201216/">2020-12-16 Working Draft</a>
 </h3>
 
-None yet.
+* Included [=style containment=] in the ''strict'' and ''content'' keywords.
 
 <h3 id="changes-since-2020-06-03">
 Changes from <a href="https://www.w3.org/TR/2020/WD-css-contain-2-20200603/">2020-06-03 Working Draft</a>