Update README-JA.md

[Loner46]

Translated to Japanese parts which were written in English.

Checklist:

• I have read freeCodeCamp's contribution guidelines.
• My pull request has a descriptive title (not a vague title like Update index.md)
• My pull request targets the main branch of freeCodeCamp.

Closes #XXXXX

[Frenchcoder294]

I,ve got the same problem and the pull request is not successfully being sent, what can we do?

[Try2079]

Hi, your Check README Suffixes / check-readme-suffixes (pull_request) fail just like me, I wonder what happens here.