message: Fix typo in Javadoc tag for sign() return description.
diff: @@ -37,7 +37,7 @@ public interface PublicKeySign {
  /**
  * Computes the signature for {@code data}.
  *
  - * @return the signature of {$code data}
  + * @return the signature of {@code data}
  */
  byte[] sign(final byte[] data) throws GeneralSecurityException;
  }
  