RMAIL should ask for confirmation before sending mail

[Jim Van Zandt]

Recently RMAIL started asking for confirmation before deleting marked
messages.  I appreciate this, having occasionally deleted messages
prematurely in the past.

I propose that mail-send-and-exit also ask for confirmation.  Several
times, I have accidentally sent mail before I had finished editing it.
This can be embarrassing, especially when there are a lot of
addressees.  I believe that makes mail-send-and-exit a "dangerous"
command. 

I may make the mistake because mail-send-and-exit is bound to C-c C-c,
which in the related RMAIL edit mode runs the comparatively safe
command rmail-cease-edit.  I think in general one should avoid binding
safe and dangerous commands to the same key, at least in related edit
modes.  On the other hand, my fingers have learned C-c C-c as the way
to finish both modes.  Asking for confirmation seems the appropriate
extra measure of protection for the dangerous command.

                - Jim Van Zandt