Fixed #18445 -- Added a links in the docs.

Thanks Audrey Roy for the patch.

AUTHORS

@@ -453,6 +453,7 @@ answer newbie questions, and generally made Django that much better:
     Armin Ronacher
     Daniel Roseman <http://roseman.org.uk/>
     Rozza <ross.lawley@gmail.com>
+    Audrey Roy <http://audreymroy.com/>
     Oliver Rutherfurd <http://rutherfurd.net/>
     ryankanno
     Gonzalo Saavedra <gonzalosaavedra@gmail.com>

docs/ref/forms/validation.txt

@@ -1,3 +1,5 @@
+.. _form-and-field-validation:
+
 Form and field validation
 =========================
 

docs/topics/forms/modelforms.txt

@@ -196,10 +196,11 @@ The ``is_valid()`` method and ``errors``
 ----------------------------------------
 
 The first time you call ``is_valid()`` or access the ``errors`` attribute of a
-``ModelForm`` triggers form validation as well as :ref:`model validation
-<validating-objects>`. This has the side-effect of cleaning the model you pass
-to the ``ModelForm`` constructor. For instance, calling ``is_valid()`` on your
-form will convert any date fields on your model to actual date objects.
+``ModelForm`` triggers :ref:`form validation <form-and-field-validation>` as
+well as :ref:`model validation <validating-objects>`. This has the side-effect
+of cleaning the model you pass to the ``ModelForm`` constructor. For instance,
+calling ``is_valid()`` on your form will convert any date fields on your model
+to actual date objects.
 
 
 The ``save()`` method