Fix the document of parameter x in embed_id
Fix the document of parameter x in embed_id

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