Wrong link to tutorial.html

[over110]

I found some link of the Chainer tutorial page is wrong. On this page, there are two links "チュートリアルを始める" to tutorial.html. The first one links to https://tutorials.chainer.org/ja/tutorial.html, the second one links to https://tutorials.chainer.org/tutorial.html, which is 404 Not Found. I think the second one should link to https://tutorials.chainer.org/ja/tutorial.html.