Fixed cupy document link
Fixed cupy document link

delta2323/chainer,ronekko/chainer,jnishi/chainer,wkentaro/chainer,keisuke-umezawa/chainer,aonotas/chainer,ktnyt/chainer,okuta/chainer,kashif/chainer,tkerola/chainer,keisuke-umezawa/chainer,wkentaro/chainer,jnishi/chainer,niboshi/chainer,chainer/chainer,ktnyt/chainer,anaruse/chainer,niboshi/chainer,jnishi/chainer,okuta/chainer,okuta/chainer,chainer/chainer,hvy/chainer,wkentaro/chainer,kiyukuta/chainer,hvy/chainer,okuta/chainer,rezoo/chainer,keisuke-umezawa/chainer,chainer/chainer,jnishi/chainer,hvy/chainer,niboshi/chainer,chainer/chainer,wkentaro/chainer,ktnyt/chainer,keisuke-umezawa/chainer,ysekky/chainer,niboshi/chainer,hvy/chainer,pfnet/chainer,ktnyt/chainer