Fix: Add missing API sections to non-English 4.x documentation

[Farhan291]

Description

Fixes broken anchor links in all non-English versions of the 4.x API documentation by adding missing API sections.

Closes #2068

Problem

All non-English language versions only included the app section, causing broken anchor links such as:

• #req.method ❌
• #res.send ❌
• #router ❌
• #express ❌

Example broken links:

• https://expressjs.com/de/4x/api.html#req.method
• https://expressjs.com/fr/4x/api.html#res.send

The English version works correctly: https://expressjs.com/en/4x/api.html

Root Cause

The markdown files for non-English versions only included: {% include api/en/4x/app.md %} They were missing the other four sections and their anchor tags.

Solution

Added the missing {% include %} statements and anchor tags for all API sections to match the English documentation structure:

• express.md (Express function)
• req.md (Request object)
• res.md (Response object)
• router.md (Router)

Changes Made

Updated the following files to include all 5 API sections with proper anchor tags:

• ✅ de/4x/api.md (German)
• ✅ fr/4x/api.md (French)
• ✅ es/4x/api.md (Spanish)
• ✅ it/4x/api.md (Italian)
• ✅ ja/4x/api.md (Japanese)
• ✅ pt-br/4x/api.md (Portuguese)
• ✅ zh-cn/4x/api.md (Chinese Simplified)
• ✅ zh-tw/4x/api.md (Chinese Traditional)

Testing

• [x] Tested locally using bundle exec jekyll serve
• [x] Verified all anchor links work correctly
• [x] Confirmed structure matches English version
• [x] Tested multiple languages (de, fr, es)

[netlify[bot]]

✅ Deploy Preview for expressjscom-preview ready!

Name	Link
🔨 Latest commit	7dec2548d4bb20b8c8f8f969b1ee8f88d3cba42d
🔍 Latest deploy log	https://app.netlify.com/projects/expressjscom-preview/deploys/693e2d47bfe4dd000899b100
😎 Deploy Preview	https://deploy-preview-2076--expressjscom-preview.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify project configuration.

[github-actions[bot]]

🚦 Lighthouse Results (Mobile & Desktop)

URL	Device	Perf	A11y	Best Practices
/	mobile	🔴 68	🟢 100	🟢 96
/en/blog/posts.html	mobile	🟢 98	🟢 96	🟢 96
/en/5x/api.html	mobile	🔴 73	🟢 95	🟢 96
/	desktop	🟢 100	🟢 100	🟢 96
/en/blog/posts.html	desktop	🟢 100	🟢 96	🟢 92
/en/5x/api.html	desktop	🟢 100	🟢 95	🟢 96