Log Message:
-----------
CSV NULL Documentation
Update docs to clearly explain NULL value matching behavior, per Andrew.
Backpatch to 8.4.X.
Modified Files:
--------------
pgsql/doc/src/sgml/ref:
copy.sgml (r1.88 -> r1.89)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/copy.sgml?r1=1.88&r2=1.89)