update documentation
update documentation

update documentation to refer to the correct parameter: HIDE_DOCS
manosim/django-rest-framework-docs,ekonstantinidis/django-rest-framework-docs,manosim/django-rest-framework-docs,manosim/django-rest-framework-docs,ekonstantinidis/django-rest-framework-docs,ekonstantinidis/django-rest-framework-docs