chore(macros/LearnSidebar): add Japanese translations for JavaScript

[gurezo]

Summary

@hmatrjp @potappo , @mdn-yari-ja

please review for this pull request

• issue: サイドメニュー の翻訳(JavaScript) の翻訳 #793

Problem

• There is no Japanese translation yet

English pages

• cf. https://developer.mozilla.org/ja/docs/Learn/JavaScript
  • JavaScript building blocks
  • Introducing JavaScript objects
  • Asynchronous JavaScript
  • Client-side web APIs

Japanese pages

• cf. https://developer.mozilla.org/ja/docs/Learn/JavaScript
  • JavaScript の構成要素
  • JavaScript オブジェクトの紹介
  • 非同期 JavaScript
  • クライアントサイド Web API

before	after

Solution

translate japanese for LearnSidebar.ejs

NOTICE

@mdn/core-dev

Please merge once mdn-yari-ja is approved.

Before

• There is no Japanese translation yet

After

• tranlate japanese for LearnSidebar.ejs

[potappo]

Thanks @gurezo , translations are good.