code: func (g *Grid) RemoveItem(p Primitive) *Grid {
  	for index := len(g.items) - 1; index >= 0; index-- {
  		if g.items[index].Item == p {
  			g.items = append(g.items[:index], g.items[index+1:]...)
  		}
  	}
  	return g
  }
docs: // RemoveItem removes all items for the given primitive from the grid, keeping
  // the order of the remaining items intact.