Update README.md

[GokceOzkan]

💡 What is the current behavior?

GitHub Issue Number: #

🆕 What is the new behavior?

• Tooltip sample usage is added.

🏁 Checklist

A pull request can only be merged if all of these conditions are met (where applicable):

• x 🦮 Accessibility (a11y) features were implemented
• x 🗺️ Internationalization (i18n) - no hard coded strings
• x 📲 Responsiveness - components handle viewport changes and content overflow gracefully
• x 📄 Documentation was reviewed/updated
• x 🧪 Unit tests were added/updated and pass (dotnet test)
• x 🏗️ Successful compilation (dotnet build, changes pushed)

👨‍💻 Help & support