Correct mistakes in Japanese locale

[kosuke316]

Pull Request Checklist

Thank you for taking the time to improve Arrow! Before submitting your pull request, please check all appropriate boxes:

• [ ] 🧪 Added tests for changed code.
• [x] 🛠️ All tests pass when run locally (run tox or make test to find out!).
• [x] 🧹 All linting checks pass when run locally (run tox -e lint or make lint to find out!).
• [x] 📚 Updated documentation for changed code.
• [x] ⏩ Code is up-to-date with the master branch.

If you have any questions about your code changes or any of the points above, please submit your questions along with the pull request and we will try our best to help!

Description of Changes

[codecov[bot]]

Codecov Report

Merging #873 into master will not change coverage. The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master      #873   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            9         9           
  Lines         1809      1810    +1     
  Branches       312       312           
=========================================
+ Hits          1809      1810    +1     

Impacted Files	Coverage Δ
arrow/locales.py	100.00% <100.00%> (ø)

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[krisfremen]

@kosuke316 Thank you for contributing and correcting the locale!

The tests do seem to be passing, but I noticed there are no Japanese locale tests. Would you like to add that to your pull request?

[kosuke316]

@krisfremen Thanks for the reply! I've also added a test feature. I hope you can check it out.