Log Message:
-----------
Clarify documentation of handling of null arguments for aggregates.
Per discussion.
Modified Files:
--------------
pgsql/doc/src/sgml:
func.sgml (r1.530 -> r1.531)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/func.sgml?r1=1.530&r2=1.531)
syntax.sgml (r1.153 -> r1.154)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/syntax.sgml?r1=1.153&r2=1.154)