Revise AI prompt example

[anandmeg]

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Internal previews

📄 File	🔗 Preview link
docs/csharp/how-to/parse-strings-using-split.md	How to separate strings using String.Split in C#
docs/csharp/programming-guide/types/how-to-convert-a-string-to-a-number.md	How to convert a string to a number (C# Programming Guide)

[Copilot]

Pull request overview

This PR revises the AI prompt example in the C# documentation for string splitting using String.Split. The changes improve the example by using a more realistic CSV-style parsing scenario instead of a simpler sentence-splitting example.

Key changes:

• Updated the ms.date metadata field
• Revised the Copilot prompt example to demonstrate CSV parsing with multiple delimiters and whitespace handling
• Improved the disclaimer text by splitting it into clearer, more actionable guidance

[BillWagner]

Hi @anandmeg
I had a couple comments, and then this is ready.

[BillWagner]

This LGTM. I'll now.