message: Fixing a typo.
diff: @@ -145,7 +145,7 @@ final class Ed25519 {
  Field25519.mult(rhs, rhs, D);
  // rhs = z^4 + D * x^2 * y^2
  Field25519.sum(rhs, z4);
  - // Field25519.mult reduces its output, but Field25519.sub does not, so we have to manually
  + // Field25519.mult reduces its output, but Field25519.sum does not, so we have to manually
  // reduce it here.
  Field25519.reduce(rhs, rhs);
  // z^2 (y^2 - x^2) == z^4 + D * x^2 * y^2
  