code: func lintHelp(mf dto.MetricFamily) []Problem {
  	var problems problems
  
  	// Expect all metrics to have help text available.
  	if mf.Help == nil {
  		problems.Add(mf, "no help text")
  	}
  
  	return problems
  }
docs: // lintHelp detects issues related to the help text for a metric.