fixup: drop no-longer needed TODO

Author: daviddrysdale

p256/src/ecdsa.rs

@@ -231,8 +231,6 @@ mod tests {
                         let verify_key =
                             ecdsa_core::VerifyingKey::from_encoded_point(&q_encoded).unwrap();
 
-                        // TODO: this only works in release builds, because there's a `debug_assert_eq`
-                        // in der.rs that prevents the Err being emitted.
                         let sig = match Signature::from_der(sig) {
                             Ok(s) => s,
                             Err(_) if !pass => return None,