[1.5.x] Fixed #20763 -- Typo in tutorial 3.
[1.5.x] Fixed #20763 -- Typo in tutorial 3.

Thanks crichard@ for the report.

Backport of fd95dc9e27 from master

alx-eu/django,bliti/django-nonrel-1.5,ccn-2m/django,hasadna/django,ccn-2m/django,ccn-2m/django,imtapps/django-imt-fork,imtapps/django-imt-fork,ccn-2m/django,hasadna/django,bliti/django-nonrel-1.5,alx-eu/django,alx-eu/django,imtapps/django-imt-fork,bliti/django-nonrel-1.5,alx-eu/django,hasadna/django