Fixed typo in docs/topics/checks.txt.

docs/topics/checks.txt

@@ -151,7 +151,7 @@ Fields, models, and model managers all implement a ``check()`` method that is
 already registered with the check framework. If you want to add extra checks,
 you can extend the implementation on the base class, perform any extra
 checks you need, and append any messages to those generated by the base class.
-It's recommended the you delegate each check to a separate methods.
+It's recommended that you delegate each check to separate methods.
 
 Consider an example where you are implementing a custom field named
 ``RangedIntegerField``. This field adds ``min`` and ``max`` arguments to the