[css-anchor-position-1] Fix anchor-scope step in acceptable anchor algo #11028

Author: fantasai

css-anchor-position-1/Overview.bs

@@ -457,7 +457,7 @@ in anchor positioning.
 		or a fully styleable [=tree-abiding pseudo-element=].
 
 	* |possible anchor| is in scope for |positioned el|,
-		per the effects of 'anchor-scope' on |positioned el|
+		per the effects of 'anchor-scope' on |possible anchor|
 		or its ancestors.
 
 	* |possible anchor| is laid out strictly before |positioned el|,