update deferBlockBehavior documentation

Author: saubaig456

docs/angular-testing-library/api.mdx

@@ -157,8 +157,7 @@ Set the defer blocks behavior.
 For more info see the
 [Angular docs](https://angular.io/api/core/testing/DeferBlockBehavior)
 
-**default** : `undefined` (uses the Angular default, which is
-`DeferBlockBehavior.Manual`)
+**default** : `undefined` (uses `DeferBlockBehavior.Manual`, which is different from the Angular default of `DeferBlockBehavior.Playthrough`)
 
 **example**: