pgsql: Fix a bunch of bad grammar in the docs: ", which see for

Log Message:
-----------
Fix a bunch of bad grammar in the docs: "<link>, which see for more
information" is un-good English.

Modified Files:
--------------
    pgsql/doc/src/sgml:
        ddl.sgml (r1.74 -> r1.75)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ddl.sgml.diff?r1=1.74&r2=1.75)
    pgsql/doc/src/sgml/ref:
        alter_role.sgml (r1.7 -> r1.8)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/alter_role.sgml.diff?r1=1.7&r2=1.8)
        alter_user.sgml (r1.42 -> r1.43)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/alter_user.sgml.diff?r1=1.42&r2=1.43)
        begin.sgml (r1.35 -> r1.36)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/begin.sgml.diff?r1=1.35&r2=1.36)
        create_group.sgml (r1.17 -> r1.18)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_group.sgml.diff?r1=1.17&r2=1.18)
        create_user.sgml (r1.39 -> r1.40)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_user.sgml.diff?r1=1.39&r2=1.40)
        createlang.sgml (r1.40 -> r1.41)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/createlang.sgml.diff?r1=1.40&r2=1.41)
        drop_group.sgml (r1.13 -> r1.14)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/drop_group.sgml.diff?r1=1.13&r2=1.14)
        drop_user.sgml (r1.23 -> r1.24)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/drop_user.sgml.diff?r1=1.23&r2=1.24)