Bug 7825: (follow-up) clarify the yes and no values

Bug 7825: (follow-up) clarify the yes and no values

The value of the pref should be '1' (for yes) or '0' (for no).
The options could be kept as 'yes' and 'no': since the ImplicitTyping is
set, yes/no would become '1/0'. But I think it is preferable not to use
the yes/no value in order not to introduce a bug here if ImplicitTyping
is unset later.

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>