pgsql: Fix broken markup and spelling, put paragraph in a somewhat less

Log Message:
-----------
Fix broken markup and spelling, put paragraph in a somewhat less random
place.

Modified Files:
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pgsql/doc/src/sgml:
func.sgml (r1.274 -> r1.275)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/func.sgml.diff?r1=1.274&r2=1.275)