pgsql: Make an editorial pass over the newly SGML-ified contrib

Log Message:
-----------
Make an editorial pass over the newly SGML-ified contrib documentation.
Fix lots of bad markup, bad English, bad explanations.

This commit covers only about half the contrib modules, but I grow weary...

Modified Files:
--------------
    pgsql/doc/src/sgml:
        adminpack.sgml (r1.2 -> r1.3)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/adminpack.sgml?r1=1.2&r2=1.3)
        btree-gist.sgml (r1.3 -> r1.4)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/btree-gist.sgml?r1=1.3&r2=1.4)
        chkpass.sgml (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/chkpass.sgml?r1=1.1&r2=1.2)
        contrib-spi.sgml (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/contrib-spi.sgml?r1=1.1&r2=1.2)
        contrib.sgml (r1.7 -> r1.8)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/contrib.sgml?r1=1.7&r2=1.8)
        cube.sgml (r1.4 -> r1.5)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/cube.sgml?r1=1.4&r2=1.5)
        dblink.sgml (r1.2 -> r1.3)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/dblink.sgml?r1=1.2&r2=1.3)
        dict-int.sgml (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/dict-int.sgml?r1=1.1&r2=1.2)
        dict-xsyn.sgml (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/dict-xsyn.sgml?r1=1.1&r2=1.2)
        earthdistance.sgml (r1.2 -> r1.3)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/earthdistance.sgml?r1=1.2&r2=1.3)
        fuzzystrmatch.sgml (r1.2 -> r1.3)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/fuzzystrmatch.sgml?r1=1.2&r2=1.3)
        hstore.sgml (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/hstore.sgml?r1=1.1&r2=1.2)
        lo.sgml (r1.2 -> r1.3)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/lo.sgml?r1=1.2&r2=1.3)
        seg.sgml (r1.3 -> r1.4)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/seg.sgml?r1=1.3&r2=1.4)
        sslinfo.sgml (r1.2 -> r1.3)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/sslinfo.sgml?r1=1.2&r2=1.3)
        tablefunc.sgml (r1.3 -> r1.4)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/tablefunc.sgml?r1=1.3&r2=1.4)
        test-parser.sgml (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/test-parser.sgml?r1=1.1&r2=1.2)
        tsearch2.sgml (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/tsearch2.sgml?r1=1.1&r2=1.2)
        uuid-ossp.sgml (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/uuid-ossp.sgml?r1=1.1&r2=1.2)
        vacuumlo.sgml (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/vacuumlo.sgml?r1=1.1&r2=1.2)
        xml2.sgml (r1.3 -> r1.4)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/xml2.sgml?r1=1.3&r2=1.4)