func GenYamlTreeCustom(cmd *cobra.Command, dir string, filePrepender, linkHandler func(string) string) error {
	for _, c := range cmd.Commands() {
		if !c.IsAvailableCommand() || c.IsAdditionalHelpTopicCommand() {
			continue
		}
		if err := GenYamlTreeCustom(c, dir, filePrepender, linkHandler); err != nil {
			return err
		}
	}
	basename := strings.Replace(cmd.CommandPath(), " ", "_", -1) + ".yaml"
	filename := filepath.Join(dir, basename)
	f, err := os.Create(filename)
	if err != nil {
		return err
	}
	defer f.Close()
	if _, err := io.WriteString(f, filePrepender(filename)); err != nil {
		return err
	}
	if err := GenYamlCustom(cmd, f, linkHandler); err != nil {
		return err
	}
	return nil
}
GenYamlTreeCustom creates yaml structured ref files.
package doc
import (
	"fmt"
	"io"
	"os"
	"path/filepath"
	"sort"
	"strings"
	"github.com/spf13/cobra"
	"github.com/spf13/pflag"
	"gopkg.in/yaml.v2"
)
type cmdOption struct {
	Name         string
	Shorthand    string `yaml:",omitempty"`
	DefaultValue string `yaml:"default_value,omitempty"`
	Usage        string `yaml:",omitempty"`
}
type cmdDoc struct {
	Name             string
	Synopsis         string      `yaml:",omitempty"`
	Description      string      `yaml:",omitempty"`
	Options          []cmdOption `yaml:",omitempty"`
	InheritedOptions []cmdOption `yaml:"inherited_options,omitempty"`
	Example          string      `yaml:",omitempty"`
	SeeAlso          []string    `yaml:"see_also,omitempty"`
}
func GenYamlTree(cmd *cobra.Command, dir string) error {
	identity := func(s string) string { return s }
	emptyStr := func(s string) string { return "" }
	return GenYamlTreeCustom(cmd, dir, emptyStr, identity)
}