Add trailing newline to ipv6.rs

Author: CDirkx

src/test/ui/consts/std/net/ipv6.rs

@@ -50,4 +50,4 @@ fn main() {
 
     const IP_V4 : Option<Ipv4Addr> = IP_ADDRESS.to_ipv4();
     assert_eq!(IP_V4.unwrap(), Ipv4Addr::new(0, 0, 0, 1));
-}
+}