code: func MainUsageTemplate() string {
  	sections := []string{
  		"\n\n",
  		SectionVars,
  		SectionAliases,
  		SectionExamples,
  		SectionSubcommands,
  		SectionFlags,
  		SectionUsage,
  		SectionTipsHelp,
  		SectionTipsGlobalOptions,
  	}
  	return strings.TrimRightFunc(strings.Join(sections, ""), unicode.IsSpace)
  }
docs: // MainUsageTemplate if the template for 'usage' used by most commands.