As far as I can tell, there's no way to determine in a send-hook if
the message is a reply. Is that right?
This is the most obvious thing to try, but it doesn't work because ~h
is invalid in the context of a send-hook:
send-hook '=h In-Reply-To:' ...
Here's what I'm using presently, but I'd prefer something more
definitive:
send-hook '~s "^Re:"' ...
Thanks,
Aron