Add prompt for adding a new language to Next.js using next-intl (#34)

* Add prompt for adding a new language to Next.js using next-intl

* Update README and prompt for Next.js i18n integration with next-intl

Author: tgrall

README.md

@@ -58,6 +58,7 @@ Ready-to-use prompt templates for specific development scenarios and tasks, defi
 - [Multi Stage Dockerfile](prompts/multi-stage-dockerfile.prompt.md) - Create optimized multi-stage Dockerfiles for any language or framework
 - [My Issues](prompts/my-issues.prompt.md) - List my issues in the current repository
 - [My Pull Requests](prompts/my-pull-requests.prompt.md) - List my pull requests in the current repository
+- [Next Intl Add Language](prompts/next-intl-add-language.prompt.md) - Add new language to a Next.js + next-intl application
 
 > 💡 **Usage**: Use `/prompt-name` in VS Code chat, run `Chat: Run Prompt` command, or hit the run button while you have a prompt open.
 

prompts/next-intl-add-language.prompt.md

@@ -0,0 +1,20 @@
+---
+mode: 'agent'
+tools: ['changes','codebase', 'editFiles', 'findTestFiles', 'search', 'writeTest']
+description: 'Add new language to a Next.js + next-intl application'
+---
+
+This is a guide to add a new language to a Next.js project using next-intl for internationalization,
+
+- For i18n, the application uses next-intl.
+- All translations are in the directory `./messages`.
+- The UI component is `src/components/language-toggle.tsx`.
+- Routing and middleware configuration are handled in:
+  - `src/i18n/routing.ts`
+  - `src/middleware.ts`
+
+When adding a new language:
+
+- Translate all the content of `en.json` to the new language. The goal is to have all the JSON entries in the new language for a complete translation.
+- Add the path in `routing.ts` and `middleware.ts`.
+- Add the language to `language-toggle.tsx`.