Make Japanese as available language on documentation

[luixxiul]

Since documentation has been translated into Japanese completely, fixing a bunch of strings wrongly translated as well, I would like to ask the team to add Japanese as available language by adding it on https://github.com/onionshare/onionshare/blob/main/docs/build.sh#L6, 1e3ec0d#diff-008dcb3426febd767787b1521f1fe33086313b927ea37eaab86df5fa88a51698R15, etc.

[SaptakS]

Thanks for pointing this out. I will do the needful.