Update testing doc

Author: alex35mil

docs/testing.md

@@ -3,7 +3,7 @@
 ## Gotchas
 
 ### Triggering validation on `change`/`blur` events
-When testing `on*` strategies (e.g. `onFirstChange`, `onFirstBlur`) set next props **before** simulate event, that triggers validation. Otherwise obsolete props will be passed to validator:
+When testing sync strategies (e.g. `onFirstChange`, `onFirstBlur`) set next props **before** simulate event, that triggers validation. Otherwise obsolete props will be passed to validator:
 
 ```js
 /* strategy: 'onFirstChange' */
@@ -12,5 +12,3 @@ Form.setProps({ data: { email: '[email protected]' } }); // <= update data first
 Form.find('.input').simulate('change');                // <= trigger event -> validation
 expect(/* ... */)).toBe(/* ... */);
 ```
-
-Since `instant`-type strategies validate all fields on props update (in lifecycle hooks), just setting next props should be fine.