Bad link in lesson 1

[MrYossu]

Near the top of the readme.md for lesson 1 is a link Understanding tokens in Azure OpenAI, but the target gives a 404.

Please can this be fixed.

[github-actions]

👋 Thanks for contributing @MrYossu! We will review the issue and get back to you soon.

[elbruno]

Fixed! The broken link to /azure/ai-services/openai/concepts/tokens\ has been replaced with a working link to Key concepts and considerations in generative AI, which covers tokens, context windows, and pricing.

We also ran a full link audit and fixed 6 additional broken links across the lesson docs. Thanks for reporting this! 🙏