add F.shift to docs
add F.shift to docs

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