refactor: move i/e/n/errorx to i/errorsx (#416)

Still working towards https://github.com/ooni/probe/issues/1505

internal/netxlite/legacy.go

@@ -4,7 +4,7 @@ import (
 	"errors"
 	"strings"
 
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/errorx"
+	"github.com/ooni/probe-cli/v3/internal/errorsx"
 )
 
 // reduceErrors finds a known error in a list of errors since
@@ -27,7 +27,7 @@ func reduceErrors(errorslist []error) error {
 	// the user has no IPv6 connectivity, an IPv6 error is going to
 	// appear later in the list of errors.
 	for _, err := range errorslist {
-		var wrapper *errorx.ErrWrapper
+		var wrapper *errorsx.ErrWrapper
 		if errors.As(err, &wrapper) && !strings.HasPrefix(
 			err.Error(), "unknown_failure",
 		) {

internal/netxlite/legacy_test.go

@@ -4,7 +4,7 @@ import (
 	"errors"
 	"testing"
 
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/errorx"
+	"github.com/ooni/probe-cli/v3/internal/errorsx"
 )
 
 func TestReduceErrors(t *testing.T) {
@@ -31,15 +31,15 @@ func TestReduceErrors(t *testing.T) {
 	})
 	t.Run("multiple errors with meaningful ones", func(t *testing.T) {
 		err1 := errors.New("mocked error #1")
-		err2 := &errorx.ErrWrapper{
+		err2 := &errorsx.ErrWrapper{
 			Failure: "unknown_failure: antani",
 		}
-		err3 := &errorx.ErrWrapper{
-			Failure: errorx.FailureConnectionRefused,
+		err3 := &errorsx.ErrWrapper{
+			Failure: errorsx.FailureConnectionRefused,
 		}
 		err4 := errors.New("mocked error #3")
 		result := reduceErrors([]error{err1, err2, err3, err4})
-		if result.Error() != errorx.FailureConnectionRefused {
+		if result.Error() != errorsx.FailureConnectionRefused {
 			t.Fatal("wrong result")
 		}
 	})