[readme] stringify: clarify default arrayFormat behavior

README.md

@@ -375,14 +375,14 @@ var decoded = qs.parse('x=z', { decoder: function (str, defaultDecoder, charset,
 
 Examples beyond this point will be shown as though the output is not URI encoded for clarity. Please note that the return values in these cases *will* be URI encoded during real usage.
 
-When arrays are stringified, by default they are given explicit indices:
+When arrays are stringified, they follow the `arrayFormat` option, which defaults to `indices`:
 
 ```javascript
 qs.stringify({ a: ['b', 'c', 'd'] });
 // 'a[0]=b&a[1]=c&a[2]=d'
 ```
 
-You may override this by setting the `indices` option to `false`:
+You may override this by setting the `indices` option to `false`, or to be more explicit, the `arrayFormat` option to `repeat`:
 
 ```javascript
 qs.stringify({ a: ['b', 'c', 'd'] }, { indices: false });