Meta: export observable array hooks

Author: domenic

index.bs

@@ -6835,11 +6835,11 @@ Observable array types must only be used as the type of [=regular attributes=].
 For an attribute whose type is an observable array type, specification authors can specify a series
 of algorithms:
 
-*   <dfn for="observable array attribute">set an indexed value</dfn>, which accepts an IDL value
-    that is about to be set in the observable array, and the index at which it is being set;
-*   <dfn for="observable array attribute">delete an indexed value</dfn>, which accepts an IDL value
-    that is about to be removed from the observable array, and the index from which it is being
-    removed.
+*   <dfn export for="observable array attribute">set an indexed value</dfn>, which accepts an IDL
+    value that is about to be set in the observable array, and the index at which it is being set;
+*   <dfn export for="observable array attribute">delete an indexed value</dfn>, which accepts an
+    IDL value that is about to be removed from the observable array, and the index from which it is
+    being removed.
 
 Both of these algorithms are optional, and if not provided, the default behavior will be to do
 nothing. Either algorithm may throw an exception, e.g. to reject invalid values.