Fix some go nits.

pkg/commands/build/build_test.go

@@ -81,7 +81,7 @@ func TestBuild(t *testing.T) {
 	updateKustomizeExpected := os.Getenv(updateEnvVar) == "true"
 	fSys := fs.MakeRealFS()
 
-	testcases := []string{}
+	var testcases []string
 	filepath.Walk("testdata", func(path string, info os.FileInfo, err error) error {
 		if err != nil {
 			return err

pkg/commands/misc/config.go

@@ -97,7 +97,7 @@ func (o *saveOptions) Complete(fsys fs.FileSystem) error {
 	if fsys.IsDir(o.saveDirectory) {
 		return nil
 	}
-	return fmt.Errorf("%s is not a directory. Please use a different directory name.", o.saveDirectory)
+	return fmt.Errorf("%s is not a directory", o.saveDirectory)
 }
 
 // RunSave saves the default transformer configurations local directory

pkg/commands/misc/config_test.go

@@ -61,7 +61,7 @@ func TestComplete(t *testing.T) {
 		},
 		{
 			dir:    "/some/file",
-			expect: fmt.Errorf("%s is not a directory. Please use a different directory name.", "/some/file"),
+			expect: fmt.Errorf("%s is not a directory", "/some/file"),
 		},
 	}