Log Message:
-----------
Fix incorrect backslashing in regexp example, per Robert Treat.
Modified Files:
--------------
pgsql/doc/src/sgml/ref:
create_domain.sgml (r1.20 -> r1.21)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_domain.sgml.diff?r1=1.20&r2=1.21)