Support priority on Mail.Options (#34720)
Support priority on Mail.Options (#34720)

* Support priority on Mail.Options

As stated in this file:
https://github.com/nodemailer/nodemailer/blob/master/lib/mailer/mail-message.js

* coding style errors

Error in nodemailer
Error: /home/travis/build/DefinitelyTyped/DefinitelyTyped/types/nodemailer/lib/mailer/index.d.ts:140:1
ERROR: 140:1   no-trailing-whitespace  trailing whitespace
ERROR: 141:19  typedef-whitespace      expected onespace after colon in property-declaration
ERROR: 141:19  whitespace              missing whitespace

dsebastien/DefinitelyTyped,georgemarshall/DefinitelyTyped,georgemarshall/DefinitelyTyped,georgemarshall/DefinitelyTyped,georgemarshall/DefinitelyTyped,dsebastien/DefinitelyTyped,mcliment/DefinitelyTyped,markogresak/DefinitelyTyped