[css-scroll-anchoring-1] Fix anchor selection step. (#12342)

* Fix anchor selection step. Closes #11748

* Fix indentation

Author: vmpstr

css-scroll-anchoring-1/Overview.bs

@@ -142,8 +142,12 @@ non-atomic inline element as the priority candidate.
 		whose computed value of the 'overflow-anchor' property is ''overflow-anchor/none'',
 		then do not select an anchor node for |S|.
 	2. Otherwise, for each <a>priority candidate</a> |PC| in order specified,
-		check if |PC| is a <a>viable candidate</a> in |S|. If so, select it as an
-		anchor node and terminate.
+		check if |PC| is a <a>viable candidate</a> in |S|.
+		If so, perform the <a>candidate examination algorithm</a> for |PC| in |S| and terminate.
+
+		Note: Since the priority candidate itself is checked to be viable, the <a>candidate examination algorithm</a>
+		is guaranteed to select at least the candidate node itself.
+
 	3. Otherwise, for each DOM child |N| of the element or document associated with |S|,
 		perform the <a>candidate examination algorithm</a> for |N| in |S|,
 		and terminate if it selects an anchor node.
@@ -345,3 +349,4 @@ Changes Since the Feb 11 2020 Working Draft</h3>
 
 	* Added definitions of [=viable candidate=] and [=priority candidate=].
 	* Clarified interaction between scroll anchoring and [=scroll snapping=].
+	* Added a step to run <a>candidate examination algorithm</a> on viable priority candidates.