code: func (ns nodes) tailSort() {
  	for i := len(ns) - 1; i >= 0; i-- {
  		if ns[i].typ > ntStatic && ns[i].tail == '/' {
  			ns.Swap(i, len(ns)-1)
  			return
  		}
  	}
  }
docs: // tailSort pushes nodes with '/' as the tail to the end of the list for param nodes.
  // The list order determines the traversal order.