Log Message:
-----------
Update comment associated with 'debug_query_string'.
Modified Files:
--------------
    pgsql/src/backend/tcop:
        postgres.c (r1.564 -> r1.565)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/tcop/postgres.c?r1=1.564&r2=1.565)