fix: document open in new tab

[dylantientcheu]

Summary

• Documents the solution for opening DocSearch results in new tabs
• Adds a new section to the examples page explaining the hitComponent + navigator approach
• Provides working code examples and interactive demo

Problem

In DocSearch, using only hitComponent with target="_blank" doesn't work consistently - it opens links in new tabs when clicked, but keyboard navigation (arrows + Enter) still opens links in the same window.

Solution

This PR documents the complete solution that requires both:

1. Custom hitComponent with target="_blank" for click behavior
2. Custom navigator prop to handle keyboard navigation consistently

Changes

• Added "Opening links in new tabs" section to docs/examples.mdx
• Includes code examples showing both hitComponent and navigator setup
• Added interactive demo component
• Added warning note explaining why both props are needed

Fixes #2702

[netlify]

✅ Deploy Preview for docsearch ready!

Name	Link
🔨 Latest commit	620df47
🔍 Latest deploy log	https://app.netlify.com/projects/docsearch/deploys/68b02db077f8210008f8c987
😎 Deploy Preview	https://deploy-preview-2737--docsearch.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.