Fix documentation of check_option in information_schema.views

Support of CHECK OPTION for updatable views has been added in 9.4, but
the documentation of information_schema never got the call even if the
information displayed is correct.

Author: Gilles Darold
Discussion: https://postgr.es/m/75d07704-6c74-4f26-656a-10045c01a17e@darold.net
Backpatch-through: 9.4