Log Message:
-----------
Document that btrim()'s second parameter is optional, and defaults to spaces.
Modified Files:
--------------
pgsql/doc/src/sgml:
func.sgml (r1.225 -> r1.226)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/func.sgml.diff?r1=1.225&r2=1.226)