Wish: notmuch-emacs: allow for reply to attached message/rfc822 message

[Gregor Zattler]

Dear notmuch developers,

it would be great if it was possible in notmuch-emacs to reply to
the very mime part of a message, the cursor is in.

Use case: Mailman sends emails for approval to list owners where
the last mime parts are a rfc822 attachment to which said list
owner may answer in order to delete the pending message from the
mailman queue (approval is more difficult).

In mutt (1) for instance it is possible to show the mime
structure of an email, show only a specific one and -- in case
its message/rfc822 -- reply to this.  This is very convenient.

[This being emacs I then tried to open mailmans web interface
from within emacs but in the end an error occurred an I had to
use firefox.]

Thanks for your attention, Gregor