[css-backgrounds-4] Allowed combining border-area and text in background-clip #10696 (#12738)

Author: SebastianZ

css-backgrounds-4/Overview.bs

@@ -326,7 +326,7 @@ Painting Area: the 'background-clip' property</h3>
 	The syntax of the property is given with
 
 	<pre class=prod>
-	<dfn>&lt;bg-clip></dfn> = <<visual-box>> | border-area| text
+	<dfn>&lt;bg-clip></dfn> = <<visual-box>> | [ border-area || text ]
 	</pre>
 
 	Issue: Or should this be defining the <css>-webkit-background-clip</css> property,