Replying does not decode UTF-8 addresses

[The-Compiler]

When I reply to a mail that gets shown as From: Firstname Sjökvist in the UI, the draft and reply show To: =?utf-8?q?Firstname_Sj=C3=B6kvist?= <firstname@example.org>.

I haven't tried how that actually arrives when sending (i.e. whether that gets escaped again to a literal =?utf8?...), but IMHO:

• The draft and editor should show this as To: Firstname Sjökvist
• Only when sending, that should be encoded accordingly

[hbog]

This seems to be a regression caused by 7531707, and more specific usage of the function email.utils.formataddr, which 'header-encodes' the name:

>>> email.utils.formataddr(('Céline', 'celine@example.org'))
'=?utf-8?q?C=C3=A9line?= <celine@example.org>'

Source: emails.util.formataddr

[hbog]

One solution could be not to touch the address headers (they are already properly formatted by notmuch) and use notmuch-reply to construct the reply template. It also adds "In-Reply-To" and "References" headers. In other words let notmuch do the heavy lifting.