Code review comment for lp:~daker/launchpad/fix.1600499

Thanks for reply, i just checked LP emails, indeed it's sent as text/plain, to solve this the email need to be sent as multipart/alternative, which then will include both versions the text/plain & text/html, the email client will choose which version to display depending on the user settings, here is the markup reference https://developers.google.com/gmail/markup/reference/go-to-action#view_action