How to enable X-Forwarded-For Header in WebProxy?

How can I enable the X-Forwarded-For header in the webproxy? I see the option is disabled inside the file but i am unable to modify the value. This is what I see:

# default to NOT insert the client address in X-Forwarded-For header
$output .= “forwarded_for off\n\n”;

Any help would be appreciated! Thanks

EDIT - SOLVED!: Sorry for the newbie mistake, I did not try using simply ‘sudo vi’ to edit the file. I did this and changed it from "$output .= “forwarded_for off\n\n” to "$output .= “forwarded_for on\n\n:” and reset the vyos.
Everything is up and now showing the X-Forwarded-For information. I was able to validate this by running tcpdump on an upstream device. For reference: tcpdump -vvvs 1024 -l -A -i | grep Forwarded-For