[racket-dev] adding preferences

I currently have a preference to enabling/disabling line numbers in the
'view' menu which is easy to set up in drracket/collects/main.rkt. A
user asked me to add a checkbox they could select in
edit->preferences->general which I see is controlled by
framework/private/preferences.rkt but I can't seem to get a reference to
the definitions text from there. I suppose I can make the preference set
the 'drracket:show-line-numbers property but it would be nice if it
could dynamically update the line numbers, much like 'view->show line
numbers' currently does.

Is there a way to get to the definitions text in those callbacks?