Add reference to Japanese translation on the homepage

[gemmaro]

Hello,

I've translated the following rbenv-related repositories into Japanese to support Japanese-speaking developers:

• rbenv.github.io
• rbenv
• ruby-build

This adds a link to the Japanese translation page on the respective top page.

Thank you,

[mislav]

Hello, thank you for working hard on the translations!

I would feel better about having a translation on the rbenv.org site itself, rather than linking to a separate site that is a fork. That way I believe the content could stay up-to-date in the long term and contributed to in the central repository (this one).

Does that sound good and would you be open to restructure your PR so that it adds translations of index.html and rbenv/ruby-build man pages under the https://rbenv.org/ja/ URL? Also, the po4a recipes could be added to our existing Makefile in the root directory, rather than being in a separate Makefile. Thank you!

Additionally, I don't think it's necessary to call out to the existence of "Ruby STUDIO/rbenv". That page is severely out of date and, since we're not affiliated with it and since you haven't borrowed translations from there, I would suggest to not mention it at all to avoid confusion.

[gemmaro]

Thank you for your feedback!

I agree with keeping the translation on rbenv.org to ensure it stays up-to-date, and I’m on board with the proposed URL structure for the localized pages.
I’ll also remove the links to the previous translation works as you suggested.

Here’s my proposed plan. Does it sound okay to proceed?

1. Add translation sources and corresponding Make tasks to the rbenv and ruby-build repositories.
2. Add translation sources and Make tasks to this repository as well --- including pulling translations from the rbenv and ruby-build directories.

[gemmaro]

Hi, I’ve opened the pull request rbenv/rbenv#1624 to get your feedback on whether the overall direction looks good.
If this approach seems appropriate, I’d like to go ahead and open similar pull requests for the ruby-build and this rbenv.github.io repositories as well.
Thanks in advance for taking a look!