Log Message:
-----------
Document that NOT NULL domain constraints are not always honored.
Modified Files:
--------------
pgsql/doc/src/sgml/ref:
create_domain.sgml (r1.34 -> r1.35)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_domain.sgml?r1=1.34&r2=1.35)