Log Message:
-----------
Improve documentation about function volatility: mention the snapshot
visibility effects in a couple of places where people are likely to look
for it. Per discussion of recent question from Karl Nack.
Modified Files:
--------------
pgsql/doc/src/sgml:
trigger.sgml (r1.55 -> r1.56)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/trigger.sgml?r1=1.55&r2=1.56)
xfunc.sgml (r1.137 -> r1.138)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/xfunc.sgml?r1=1.137&r2=1.138)