pgsql: Desultorily enclose programlisting tags in CDATA, to get rid of

Log Message:
-----------
Desultorily enclose programlisting tags in CDATA, to get rid of some obnoxious
SGML-escaping.

Modified Files:
--------------
    pgsql/doc/src/sgml:
        auto-explain.sgml (r1.1 -> r1.2)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/auto-explain.sgml?r1=1.1&r2=1.2)
        ecpg.sgml (r1.86 -> r1.87)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ecpg.sgml?r1=1.86&r2=1.87)
        libpq.sgml (r1.272 -> r1.273)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/libpq.sgml?r1=1.272&r2=1.273)
        lobj.sgml (r1.48 -> r1.49)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/lobj.sgml?r1=1.48&r2=1.49)
        trigger.sgml (r1.52 -> r1.53)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/trigger.sgml?r1=1.52&r2=1.53)
        xfunc.sgml (r1.134 -> r1.135)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/xfunc.sgml?r1=1.134&r2=1.135)
        xindex.sgml (r1.63 -> r1.64)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/xindex.sgml?r1=1.63&r2=1.64)
        xtypes.sgml (r1.30 -> r1.31)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/xtypes.sgml?r1=1.30&r2=1.31)