[css-contain-3] Update syntax for size-queries w3c#6870 & allow general-enclosed w3c#6396

Author: mirisuzanne

css-contain-3/Overview.bs

@@ -339,7 +339,7 @@ Container Queries</h2>
 					width: 100px;
 					container-type: inline-size;
 				}
-				@container size(inline-size < 150px) {
+				@container (inline-size < 150px) {
 					#inner::before {
 						content: "BEFORE";
 					}
@@ -363,7 +363,7 @@ Container Queries</h2>
 							width: 100px;
 							container-type: inline-size;
 						}
-						@container size(inline-size < 150px) {
+						@container (inline-size < 150px) {
 							::slotted(span) {
 								color: green;
 							}
@@ -600,13 +600,9 @@ Container Queries: the ''@container'' rule</h3>
 	                      | <<container-query>> [ and <<container-query>> ]*
 	                      | <<container-query>> [ or <<container-query>> ]*
 	<dfn><<container-query>></dfn>     = ( <<container-condition>> )
-	                      | size( <<size-query>> )
+	                      | ( <<size-feature>> )
 	                      | style( <<style-query>> )
-
-	<dfn><<size-query>></dfn>     = <<size-feature>> | <<size-condition>>
-	<dfn><<size-condition>></dfn> = not ( <<size-query>> )
-	                 | ( <<size-query>> ) [ and ( <<size-query>> ) ]*
-	                 | ( <<size-query>> ) [ or  ( <<size-query>> ) ]*
+	                      | <<general-enclosed>>
 
 	<dfn><<style-query>></dfn>     = <<style-feature>> | <<style-condition>>
 	<dfn><<style-condition>></dfn> = not ( <<style-query>> )