Implement PartialEq + Eq for NonIdentity and NonZeroScalar (#1834)

This is done by the fact that the underlying types implement these
traits already.

Author: daxpedda

elliptic-curve/src/point/non_identity.rs

@@ -18,7 +18,7 @@ use crate::{CurveArithmetic, NonZeroScalar, Scalar};
 ///
 /// In the context of ECC, it's useful for ensuring that certain arithmetic
 /// cannot result in the identity point.
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub struct NonIdentity<P> {
     point: P,
 }

elliptic-curve/src/scalar/nonzero.rs

@@ -128,6 +128,8 @@ where
     }
 }
 
+impl<C> Eq for NonZeroScalar<C> where C: CurveArithmetic {}
+
 impl<C> From<NonZeroScalar<C>> for FieldBytes<C>
 where
     C: CurveArithmetic,
@@ -256,6 +258,15 @@ where
     }
 }
 
+impl<C> PartialEq for NonZeroScalar<C>
+where
+    C: CurveArithmetic,
+{
+    fn eq(&self, other: &Self) -> bool {
+        self.scalar.eq(&other.scalar)
+    }
+}
+
 /// Note: this is a non-zero reduction, as it's impl'd for [`NonZeroScalar`].
 impl<C, I> Reduce<I> for NonZeroScalar<C>
 where