[1.10.x] Fixed #26946 -- Clarified instructions for customizing collectstatic's ignore_patterns.

Backport of ec4a6b33a9 from master

docs/ref/contrib/staticfiles.txt

@@ -128,6 +128,8 @@ For a full list of options, refer to the commands own help by running::
 
    $ python manage.py collectstatic --help
 
+.. _customize-staticfiles-ignore-patterns:
+
 Customizing the ignored pattern list
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -136,8 +138,9 @@ Customizing the ignored pattern list
 The default ignored pattern list, ``['CVS', '.*', '*~']``, can be customized in
 a more persistent way than providing the ``--ignore`` command option at each
 ``collectstatic`` invocation. Provide a custom :class:`~django.apps.AppConfig`
-class, override the ``ignore_patterns`` attribute of this class and specify
-that class path inside your :setting:`INSTALLED_APPS` setting:
+class, override the ``ignore_patterns`` attribute of this class and replace
+``'django.contrib.staticfiles'`` with that class path in your
+:setting:`INSTALLED_APPS` setting:
 
 .. code-block:: python
 

docs/releases/1.10.txt

@@ -222,6 +222,9 @@ Minor features
   ``{% load staticfiles %}`` or ``{% load static from staticfiles %}``) and
   not worry about whether or not the ``staticfiles`` app is installed.
 
+* You can :ref:`more easily customize <customize-staticfiles-ignore-patterns>`
+  the ``collectstatic --ignore_patterns`` option with a custom ``AppConfig``.
+
 Cache
 ~~~~~