[1.5.x] Fixed #12346 -- Added a note on how to validate InlineFormSets.

Thanks johnsmith for the suggestion.

Backport of 181f63c22d from master

docs/ref/contrib/admin/index.txt

@@ -1585,9 +1585,9 @@ The ``InlineModelAdmin`` class adds:
 
 .. attribute:: InlineModelAdmin.formset
 
-    This defaults to ``BaseInlineFormSet``. Using your own formset can give you
-    many possibilities of customization. Inlines are built around
-    :ref:`model formsets <model-formsets>`.
+    This defaults to :class:`~django.forms.models.BaseInlineFormSet`. Using
+    your own formset can give you many possibilities of customization. Inlines
+    are built around :ref:`model formsets <model-formsets>`.
 
 .. attribute:: InlineModelAdmin.form
 
@@ -1653,8 +1653,9 @@ The ``InlineModelAdmin`` class adds:
 
 .. method:: InlineModelAdmin.get_formset(self, request, obj=None, **kwargs)
 
-    Returns a ``BaseInlineFormSet`` class for use in admin add/change views.
-    See the example for :class:`ModelAdmin.get_formsets`.
+    Returns a :class:`~django.forms.models.BaseInlineFormSet` class for use in
+    admin add/change views. See the example for
+    :class:`ModelAdmin.get_formsets`.
 
 Working with a model with two or more foreign keys to the same parent model
 ---------------------------------------------------------------------------

docs/ref/forms/models.txt

@@ -42,8 +42,8 @@ Model Form Functions
 .. function:: inlineformset_factory(parent_model, model, form=ModelForm, formset=BaseInlineFormSet, fk_name=None, fields=None, exclude=None, extra=3, can_order=False, can_delete=True, max_num=None, formfield_callback=None)
 
     Returns an ``InlineFormSet`` using :func:`modelformset_factory` with
-    defaults of ``formset=BaseInlineFormSet``, ``can_delete=True``, and
-    ``extra=3``.
+    defaults of ``formset=``:class:`~django.forms.models.BaseInlineFormSet`,
+    ``can_delete=True``, and ``extra=3``.
 
     If your model has more than one :class:`~django.db.models.ForeignKey` to
     the ``parent_model``, you must specify a ``fk_name``.

docs/topics/forms/modelforms.txt

@@ -754,14 +754,16 @@ than that of a "normal" formset. The only difference is that we call
 ``formset.save()`` to save the data into the database. (This was described
 above, in :ref:`saving-objects-in-the-formset`.)
 
-Overiding ``clean()`` on a ``model_formset``
+.. _model-formsets-overriding-clean:
+
+Overriding ``clean()`` on a ``ModelFormSet``
 --------------------------------------------
 
 Just like with ``ModelForms``, by default the ``clean()`` method of a
-``model_formset`` will validate that none of the items in the formset violate
+``ModelFormSet`` will validate that none of the items in the formset violate
 the unique constraints on your model (either ``unique``, ``unique_together`` or
 ``unique_for_date|month|year``).  If you want to override the ``clean()`` method
-on a ``model_formset`` and maintain this validation, you must call the parent
+on a ``ModelFormSet`` and maintain this validation, you must call the parent
 class's ``clean`` method::
 
     class MyModelFormSet(BaseModelFormSet):
@@ -859,6 +861,8 @@ primary key that isn't called ``id``, make sure it gets rendered.)
 Inline formsets
 ===============
 
+.. class:: models.BaseInlineFormSet
+
 Inline formsets is a small abstraction layer on top of model formsets. These
 simplify the case of working with related objects via a foreign key. Suppose
 you have these two models::
@@ -888,6 +892,13 @@ a particular author, you could do this::
 
     :ref:`Manually rendered can_delete and can_order <manually-rendered-can-delete-and-can-order>`.
 
+Overriding ``clean()`` on an ``InlineFormSet``
+----------------------------------------------
+
+See :ref:`model-formsets-overriding-clean`, but subclass
+:class:`~models.BaseInlineFormSet` rather than
+:class:`~models.BaseModelFormSet`.
+
 More than one foreign key to the same model
 -------------------------------------------