We currently have no way of specifying the sender's name inside the
From field, making a patch sent through `git send-email` appear as
coming from "xxx@domain.com".
In this commit we make this field follow the standard
realName <email>
format.
If a user using msmtp to send all their email, it would be preferred if
git used it as well.
The only settings necessary are to set the smtp server to the msmtp
binary and set envelop sender to true, which makes git call msmtp with
the -f flag to set the from address from the email.
