pgsql: Entity-ify a passel of & < > characters.

Log Message:
-----------
Entity-ify a passel of & < > characters.  Per gripe from Devrim.

Modified Files:
--------------
    pgsql/doc/src/sgml:
        btree-gist.sgml (r1.2 -> r1.3)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/btree-gist.sgml?r1=1.2&r2=1.3)
        cube.sgml (r1.3 -> r1.4)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/cube.sgml?r1=1.3&r2=1.4)
        datatype.sgml (r1.220 -> r1.221)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/datatype.sgml?r1=1.220&r2=1.221)
        ddl.sgml (r1.79 -> r1.80)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ddl.sgml?r1=1.79&r2=1.80)
        dml.sgml (r1.16 -> r1.17)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/dml.sgml?r1=1.16&r2=1.17)
        earthdistance.sgml (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/earthdistance.sgml?r1=1.1&r2=1.2)
        ecpg.sgml (r1.84 -> r1.85)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ecpg.sgml?r1=1.84&r2=1.85)
        func.sgml (r1.414 -> r1.415)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/func.sgml?r1=1.414&r2=1.415)
        fuzzystrmatch.sgml (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/fuzzystrmatch.sgml?r1=1.1&r2=1.2)
        intarray.sgml (r1.3 -> r1.4)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/intarray.sgml?r1=1.3&r2=1.4)
        isn.sgml (r1.2 -> r1.3)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/isn.sgml?r1=1.2&r2=1.3)
        lo.sgml (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/lo.sgml?r1=1.1&r2=1.2)
        ltree.sgml (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ltree.sgml?r1=1.1&r2=1.2)
        plpgsql.sgml (r1.121 -> r1.122)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/plpgsql.sgml?r1=1.121&r2=1.122)
        pltcl.sgml (r2.46 -> r2.47)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/pltcl.sgml?r1=2.46&r2=2.47)
        release.sgml (r1.558 -> r1.559)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/release.sgml?r1=1.558&r2=1.559)
        seg.sgml (r1.2 -> r1.3)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/seg.sgml?r1=1.2&r2=1.3)
        tablefunc.sgml (r1.2 -> r1.3)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/tablefunc.sgml?r1=1.2&r2=1.3)
        trigger.sgml (r1.50 -> r1.51)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/trigger.sgml?r1=1.50&r2=1.51)
        xml2.sgml (r1.2 -> r1.3)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/xml2.sgml?r1=1.2&r2=1.3)
    pgsql/doc/src/sgml/ref:
        create_opclass.sgml (r1.20 -> r1.21)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_opclass.sgml?r1=1.20&r2=1.21)