Loosen up argument type on unexpected::Error::from

src/error/unexpected.rs

@@ -42,8 +42,11 @@ impl Error {
         return Error::from_displays(prefix, &e, e.source());
     }
 
-    pub fn from(s: &str) -> Error {
+    pub fn from<S>(s: S) -> Error
-        Error::from_displays(None::<String>, s, None::<String>)
+    where
+        S: AsRef<str>,
+    {
+        Error::from_displays(None::<String>, s.as_ref(), None::<String>)
     }
 }