code: func (f *Fpdf) AddLink() int {
  	f.links = append(f.links, intLinkType{})
  	return len(f.links) - 1
  }
docs: // AddLink creates a new internal link and returns its identifier. An internal
  // link is a clickable area which directs to another place within the document.
  // The identifier can then be passed to Cell(), Write(), Image() or Link(). The
  // destination is defined with SetLink().