style: fix fmt

Author: George-Miao

src/atomic/unsync.rs

@@ -433,9 +433,10 @@ use atomic_int;
 
 #[cfg(test)]
 mod tests {
-    use super::*;
     use std::sync::atomic::Ordering::Relaxed;
 
+    use super::*;
+
     #[test]
     fn atomic_u16_fetch_add_wraps() {
         let a = AtomicU16::new(u16::MAX);