chore(macros/LearnSidebar): add translate HTML, CSS section

[gurezo]

Summary

@hmatrjp @potappo , mdn-yari-ja

please review for this pull request

• issue: サイドメニュー の翻訳(HTML — Structuring the web, CSS — Styling the web) #790

Problem

• There is no Japanese translation yet

English pages

• cf. https://developer.mozilla.org/ja/docs/Learn/HTML
  • HTML — Structuring the web
    • Multimedia and embedding
    • HTML tables
• cf. https://developer.mozilla.org/ja/docs/Learn/CSS
  • CSS — Styling the web
    • CSS first steps
    • CSS building blocks
    • Styling text
    • CSS layout

Japanese pages

• cf. https://developer.mozilla.org/ja/docs/Learn/HTML
  • HTML — ウェブの構造化
    • マルチメディアと埋め込み
    • HTML 表
• cf. https://developer.mozilla.org/ja/docs/Learn/CSS
  • CSS — ウェブのスタイル設定
    • CSS の第一歩
    • CSS の構成要素
    • テキストの装飾
    • CSSレイアウト

section	before	after
HTML
CSS

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

[gurezo]

didn't pass CI
i'll remake prs