code: func (p Pages) Next(cur Page) Page {
  	for x, c := range p {
  		if c.Eq(cur) {
  			if x < len(p)-1 {
  				return p[x+1]
  			}
  			// TODO(bep) consider return nil here to get it line with the other Nexts
  			return p[0]
  		}
  	}
  	return nil
  }
docs: // Next returns the next page reletive to the given