Better support for helm in the address completion

[Sebastian Fischmeister]

> (setq notmuch-address-selection-function
>       (lambda (prompt collection initial-input)
>         (completing-read prompt (cons initial-input collection) nil t nil 'notmuch-address-history)))
>
> there (or use customize to do that (?)).

That's perfectly fine as well, and even simpler to use. Maybe adding
this to the emacstips page [1] under "Address completion when composing"
would be a good idea.

  Sebastian

PS: http://notmuchmail.org/emacstips/