Reassociate .NET README note on parameter type name

[kieran-ryan]

🤔 What's changed?

⚡️ What's your motivation?

Text was originally added as additional documentation for the .NET implementation.

When Python support was added (#65), the Python README example was added between the .NET code example and the .NET footnote.

This creates a source of confusion, as it now appears associated with the Python example - which is incorrect.

🏷️ What kind of change is this?

• 🏦 Refactoring/debt/DX (improvement to code design, tooling, documentation etc. without changing behaviour)

♻️ Anything particular you want feedback on?

• Whether this is globally applicable? i.e. that "custom parameters can only be used with the type name" e.g. Color for .NET, color for Python, etc.
  • If so, whether note should be made generic and moved to global scope - rather than only a specific language implementation?

📋 Checklist:

• I agree to respect and uphold the Cucumber Community Code of Conduct