[3.2.x] Fixed typo in docs/ref/forms/widgets.txt.
[3.2.x] Fixed typo in docs/ref/forms/widgets.txt.

Backport of f9cfd346f0222d86bfbac26ef5455806965bae6b from master

wkschwartz/django,koordinates/django,wkschwartz/django,koordinates/django,koordinates/django,wkschwartz/django,koordinates/django,wkschwartz/django