[css-anchor-1] Fix broken handling of non-Popover implicit anchors #12636

Author: fantasai

css-anchor-position-1/Overview.bs

@@ -368,8 +368,8 @@ in anchor positioning.
 		otherwise return nothing.
 
 	2. If |anchor spec| is ''position-anchor/auto'':
-		1. If the Popover API defines an [=implicit anchor element=] for |query el|
-			which is an [=acceptable anchor element=] for |query el|,
+		1. If |query el| has an [=implicit anchor element=]
+			that is an [=acceptable anchor element=],
 			return that element.
 
 		2. Otherwise, return nothing.