fix(email): Make doctest rustc-1.40 compatible
@@ -121,7 +121,7 @@ impl Envelope {
/// let recipients = vec![Address::from_str("to@email.com").unwrap()];
///
/// let envelope = Envelope::new(Some(sender), recipients.clone()).unwrap();
- /// assert_eq!(envelope.to(), recipients);
+ /// assert_eq!(envelope.to(), recipients.as_slice());
/// ```
pub fn to(&self) -> &[Address] {
self.forward_path.as_slice()
