[1.7.x] Fixed #21942 -- Moved Form.clean() to form API docs.

Thanks cjerdonek for the suggestion.

Backport of 874053edf9 from master

1 files changed, 6 insertions, 0 deletions

diff --git a/docs/ref/forms/api.txt b/docs/ref/forms/api.txt
index 3b687ed73d..48c6fadca1 100644
--- a/docs/ref/forms/api.txt
+++ b/docs/ref/forms/api.txt
@@ -71,6 +71,12 @@ should consider its data immutable, whether it has data or not.
 Using forms to validate data
 ----------------------------
 
+.. method:: Form.clean()
+
+Implement a ``clean()`` method on your ``Form`` when you must add custom
+validation for fields that are interdependent. See
+:ref:`validating-fields-with-clean` for example usage.
+
 .. method:: Form.is_valid()
 
 The primary task of a :class:`Form` object is to validate data. With a bound