feat: implement Debug for Deque

Author: toku-sa-n

src/deque.rs

@@ -1,3 +1,4 @@
+use core::fmt;
 use core::iter::FusedIterator;
 use core::marker::PhantomData;
 use core::mem::MaybeUninit;
@@ -374,6 +375,12 @@ impl<T, const N: usize> Drop for Deque<T, N> {
     }
 }
 
+impl<T: fmt::Debug, const N: usize> fmt::Debug for Deque<T, N> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_list().entries(self).finish()
+    }
+}
+
 /// An iterator that moves out of a [`Deque`].
 ///
 /// This struct is created by calling the `into_iter` method.