> I found out that using 'simple' instead of 'default' when using
> to_tsvector() does excactly that, but I don't know how to change my
> triggers and indexes to keep doing the same (using 'simple').
Suppose, your database is initialized with C locale. So, just mark
simple configuration as default:
# update pg_ts_cfg set locale=null where ts_name='default';
# update pg_ts_cfg set locale='C' where ts_name='simple';
If your locale setting is not C then mark needed configuration with your
locale.