pgsql: Refer to tables by id, not by "the following table", because

Log Message:
-----------
Refer to tables by id, not by "the following table", because tables are in
theory floating elements.

Modified Files:
--------------
    pgsql/doc/src/sgml:
        cube.sgml (r1.5 -> r1.6)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/cube.sgml?r1=1.5&r2=1.6)
        ecpg.sgml (r1.88 -> r1.89)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ecpg.sgml?r1=1.88&r2=1.89)
        isn.sgml (r1.4 -> r1.5)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/isn.sgml?r1=1.4&r2=1.5)
        pgbuffercache.sgml (r2.4 -> r2.5)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/pgbuffercache.sgml?r1=2.4&r2=2.5)
        pgcrypto.sgml (r1.6 -> r1.7)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/pgcrypto.sgml?r1=1.6&r2=1.7)
        pgrowlocks.sgml (r1.4 -> r1.5)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/pgrowlocks.sgml?r1=1.4&r2=1.5)
        pgstatstatements.sgml (r1.1 -> r1.2)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/pgstatstatements.sgml?r1=1.1&r2=1.2)
        pgstattuple.sgml (r1.4 -> r1.5)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/pgstattuple.sgml?r1=1.4&r2=1.5)
        seg.sgml (r1.4 -> r1.5)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/seg.sgml?r1=1.4&r2=1.5)
        xml2.sgml (r1.6 -> r1.7)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/xml2.sgml?r1=1.6&r2=1.7)