pgsql: More minor updates and copy-editing.

Log Message:
-----------
More minor updates and copy-editing.

Modified Files:
--------------
    pgsql/doc/src/sgml:
        func.sgml (r1.231 -> r1.232)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/func.sgml.diff?r1=1.231&r2=1.232)
        indices.sgml (r1.47 -> r1.48)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/indices.sgml.diff?r1=1.47&r2=1.48)
        mvcc.sgml (r2.45 -> r2.46)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/mvcc.sgml.diff?r1=2.45&r2=2.46)
        perform.sgml (r1.48 -> r1.49)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/perform.sgml.diff?r1=1.48&r2=1.49)
        typeconv.sgml (r1.42 -> r1.43)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/typeconv.sgml.diff?r1=1.42&r2=1.43)