docs: add more hooks to migration guide

[chenjiahan]

Summary

Add more hooks to migration guide:

• Added configEnvironment hook with a link to modifyEnvironmentConfig
• Expanded the description of transformIndexHtml to include the modifyHTMLTags hook.

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

[netlify]

✅ Deploy Preview for rsbuild ready!

Name	Link
🔨 Latest commit	65d4794
🔍 Latest deploy log	https://app.netlify.com/projects/rsbuild/deploys/68492e9e14ab640008abdb37
😎 Deploy Preview	https://deploy-preview-5397--rsbuild.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.
Lighthouse	1 paths audited Performance: 83 (🟢 up 9 from production) Accessibility: 97 (no change from production) Best Practices: 100 (no change from production) SEO: 100 (no change from production) PWA: 60 (no change from production) View the detailed breakdown and full score reports

---

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

[Copilot]

Pull Request Overview

This PR updates the Vite migration guide by adding the new configEnvironment hook and expanding the transformIndexHtml entry to reference the modifyHTMLTags hook.

• Introduce configEnvironment → modifyEnvironmentConfig
• Extend transformIndexHtml to include modifyHTMLTags

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
website/docs/zh/guide/migration/vite.mdx	Added configEnvironment hook and updated HTML hooks
website/docs/en/guide/migration/vite.mdx	Added configEnvironment hook and updated HTML hooks