[css-anchor-position-1] Make @position-try cascade like @Keyframe #11080

Author: fantasai

css-anchor-position-1/Overview.bs

@@ -1993,7 +1993,7 @@ The syntax of the ''@position-try'' rule is:
 The <<dashed-ident>> specified in the prelude
 is the rule's name.
 If multiple ''@position-try'' rules are declared with the same name,
-the last one in document order "wins".
+they [=cascade=] the same as ''@keyframe'' rules do.
 
 The ''@position-try'' rule only <dfn export lt="accepted @position-try properties">accepts</dfn>
 the following [=properties=]: