Add Japanese Translation for capacity statement.

[bip32JP]

On behalf of bitbank Inc. Tokyo, JP.

Thanks to btcdrak for bringing this to my attention.

[harding]

Thanks for this translation! Sorry it has taken me so long to get to it. Is there any chance you can update this line:

よくある質問の用意が進んでおり、公開後、速やかに和訳してここにて日本語版も公開する。

So that it says the same as the updated line in the English version:

For more information, please see the [FAQ](/en/bitcoin-core/capacity-increases-faq).

Thanks again.

[wbnns]

@bip32JP Hello, thank you again for this contribution. Since it has been a while and the revision requested by @harding hasn't been made, I'm closing this for now. That said, please feel free to open a new PR if you'd like to resubmit along with the requested change.