Log Message:
-----------
Make it clearer that not every Postgres character set can be used as a
server-side character set.
Modified Files:
--------------
pgsql/doc/src/sgml:
charset.sgml (r2.76 -> r2.77)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/charset.sgml.diff?r1=2.76&r2=2.77)