Don't export error testing funcs

The consumer doesn't need these yet, so there's no need to export them.

Author: jbowes

verify.go

@@ -157,13 +157,19 @@ var (
 	invalidSignatureError   = errors.New("invalid signature")
 )
 
+// These error checking funcs aren't needed yet, so don't export them
+
+/*
+
 func IsNotSignedError(err error) bool          { return errors.Is(err, notSignedError) }
 func IsMalformedSignatureError(err error) bool { return errors.Is(err, malformedSignatureError) }
 func IsUnknownKeyError(err error) bool         { return errors.Is(err, unknownKeyError) }
 func IsAlgMismatchError(err error) bool        { return errors.Is(err, algMismatchError) }
 func IsSignatureExpiredError(err error) bool   { return errors.Is(err, signatureExpiredError) }
 func IsInvalidSignatureError(err error) bool   { return errors.Is(err, invalidSignatureError) }
 
+*/
+
 func verifyRsaPssSha512(pk *rsa.PublicKey) verHolder {
 	return verHolder{
 		alg: "rsa-pss-sha512",