[css-transitions-2][css-animations-2] Specify composite order for ::marker pseudo elements

Author: birtles

css-animations-2/Overview.bs

@@ -165,6 +165,7 @@ last) as follows:
     With regard to pseudo-elements, the sort order is as follows:
 
     *  element
+    *  ::marker
     *  ::before
     *  ::after
     *  element children

css-transitions-2/Overview.bs

@@ -124,6 +124,7 @@ are sorted in composite order (first to last) as follows:
     With regard to pseudo-elements, the sort order is as follows:
 
     *  element
+    *  ::marker
     *  ::before
     *  ::after
     *  element children