Update README's auth block

[fcestari]

• Add auth to TOC
• Specify python for code block highlighting
• Format auth example

Motivation and Context

Update readme

How Has This Been Tested?

Breaking Changes

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [X] Documentation update

Checklist

• [ ] I have read the MCP Documentation
• [ ] My code follows the repository's style guidelines
• [ ] New and existing tests pass locally
• [ ] I have added appropriate error handling
• [X] I have added or updated documentation as needed

Additional context

[fcestari]

Hi @ihrpr, my pleasure. I committed the proposed changes - hopefully I got your message right. Let me know.

[ihrpr]

Thank you so much for contribution and improving the README. Sorry this PR got lost and wasn't reviewed on time. Since then, the SDK moved to the new spec, where mcp server acts as RS, hence the documentation is out of date in this PR. Closing this PR, really appreciate the help in improving the SDK.