Document the change to Array.wrap's behaviour that was made in...

Document the change to Array.wrap's behaviour that was made in b4d8c7d1

railties/guides/source/active_support_core_extensions.textile

@@ -2249,8 +2249,8 @@ The method +Array.wrap+ wraps its argument in an array unless it is already an a
 Specifically:
 
 * If the argument is +nil+ an empty list is returned.
-* Otherwise, if the argument responds to +to_ary+ it is invoked, and its result returned.
-* Otherwise, returns an array with the argument as its single element.
+* Otherwise, if the argument responds to +to_ary+ it is invoked, and if the value of +to_ary+ is not +nil+, it is returned.
+* Otherwise, an array with the argument as its single element is returned.
 
 <ruby>
 Array.wrap(nil)       # => []