[1.8.x] Added some missing newlines in docs/ref/validators.txt.
[1.8.x] Added some missing newlines in docs/ref/validators.txt.

Backport of f4cc0c40a85a8cbba6d2e4cd3158070dfd8645a2 from master

h4r5h1t/django-hauthy,pquentin/django,h4r5h1t/django-hauthy,pquentin/django,h4r5h1t/django-hauthy,h4r5h1t/django-hauthy,pquentin/django