fix: implement Debug like Display

If PhantomData<U> does not implement Debug, the Offset<T, U> does not
implement Debug, although T might implement Debug.

Signed-off-by: Harald Hoyer <harald@profian.com>

src/offset.rs

@@ -15,10 +15,16 @@ use core::ops::*;
 /// underlying types so long as the conversion is lossless for the target CPU
 /// architecture. For example, `Offset<u64>` can be converted to
 /// `Offset<usize>` on 64-bit systems.
-#[derive(Copy, Clone, Debug, Default)]
+#[derive(Copy, Clone, Default)]
 #[repr(transparent)]
 pub struct Offset<T, U>(T, PhantomData<U>);
 
+impl<T: core::fmt::Debug, U> core::fmt::Debug for Offset<T, U> {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        core::fmt::Debug::fmt(&self.0, f)
+    }
+}
+
 impl<T: core::fmt::Binary, U> core::fmt::Binary for Offset<T, U> {
     fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         core::fmt::Binary::fmt(&self.0, f)