title: Email separating character in HTML mail link is different across mail clients
body: <p>I'm pre-populating the 'Cc' and 'To' fields of an email via a <code>mailto:</code> link in HTML. When I separate the emails in the Cc field with a comma, it works in the Gmail client but not in Outlook. The opposite is true when I switch it to a semicolon.</p>
  
  <p>Is there a different separating character I should be using?</p>