Fix fmt

idna/tests/uts46.rs

@@ -161,7 +161,8 @@ fn unescape(input: &str) -> String {
                             match char::from_u32(((c1 * 16 + c2) * 16 + c3) * 16 + c4) {
                                 Some(c) => output.push(c),
                                 None => {
-                                    write!(&mut output,"\\u{:X}{:X}{:X}{:X}", c1, c2, c3, c4).expect("Could not write to output");
+                                    write!(&mut output, "\\u{:X}{:X}{:X}{:X}", c1, c2, c3, c4)
+                                        .expect("Could not write to output");
                                 }
                             };
                         }