[css-anchor-position] Fix the other reference to anchor-size() validity. w3c#9827

Author: tabatkins

css-anchor-position-1/Overview.bs

@@ -1325,7 +1325,7 @@ can use the <dfn>anchor-size()</dfn> function
 in its [=sizing properties=]
 to refer to the size of one or more [=anchor elements=].
 The ''anchor-size()'' function resolves to a <<length>>.
-It is only valid to be used in the [=sizing properties=].
+It is only valid to be used in the [=accepted @position-try properties=].
 
 The ''anchor-size()'' Function {#anchor-size-fn}
 ------------------------------