Content-type of the mime part in cited text when replying

[Tomi Ollila]

> [ text/plain ]
>>
>>     John Doe <john at doe.com> writes:
>>
>>     > [ text/plain ]
>>     > hello there
>
> (setq notmuch-mua-reply-insert-header-p-function
>       'notmuch-show-reply-insert-header-p-never)
>
> The documentation for notmuch-mua-reply-insert-header-p-function
> describes other options.
>
> We should probably change back to this ("-never") as the default.

s/probably //