code: func suggest(s string) (a []string) {
  	var g Suggestions
  	for _, c := range commands {
  		if d := editDistance(s, c.Name()); d < 4 {
  			if c.Runnable() {
  				g = append(g, Suggestion{c.Name(), d})
  			} else {
  				g = append(g, Suggestion{strconv.Quote("help " + c.Name()), d})
  			}
  		}
  	}
  	sort.Sort(g)
  	for i, s := range g {
  		a = append(a, s.s)
  		if i >= 4 {
  			break
  		}
  	}
  	return a
  }
docs: // suggest returns command names that are similar to s.