Refactored CS0077 Example with Modern C# Pattern Matching

[shethaadit]

Summary

PR Description:

This PR introduces a significant improvement to the existing example for resolving CS0077, showcasing the transition from the traditional as operator to modern C# pattern matching (is) for value types.

While the as operator is traditionally used for safe casting of reference types, applying it to non-nullable value types, such as structs, results in the CS0077 compiler error. This update replaces the outdated approach with cutting-edge pattern matching techniques, fully embracing the capabilities of C#'s modern syntax.

Key Highlights:

• Replaced unsafe use of as on a value type with pattern matching using is.
• Demonstrated how value types should be handled in casting scenarios using the type-checking and assignment capabilities of is.
• Retained the use of as for reference types, ensuring that both paradigms (reference vs. value types) are illustrated within the same example.
• This update is fully aligned with current best practices, ensuring developers adopt cleaner, more efficient, and safer code when handling type conversions.

By leveraging modern C# features, this refactor not only resolves the outdated issue but also elevates the educational value of the example, leading to more robust, readable, and maintainable code in future C# projects.

Fixes #42861

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Internal previews

📄 File	🔗 Preview link
docs/csharp/misc/cs0077.md	docs/csharp/misc/cs0077

[BartoszKlonowski]

@shethaadit Why submitting a PR to an issue that already has a comment saying someone is working on it?
Even if some time has passed since the comment, it is a good practice to ask that person whether it can be taken.

[shethaadit]

@BartoszKlonowski, I understand your concern. However, since the issue has been idle for over a week without updates, I decided to step in to keep progress moving. Let me know and I can abandon this PR.

[BartoszKlonowski]

@shethaadit No need to abandon, since you already spent some time on it.
Thing is, like I wrote: please ask person who volunteered if one still want to submit a PR. The bad luck today was that I was actually couple of minutes before submitting a PR as well, hence why saw your PR so quickly.

[BartoszKlonowski]

It looks good to me 👍
Sorry the fuss at the beginning, @shethaadit and thank you for handling this!

Let's hear from @BillWagner if there's something to improve.

[shethaadit]

It looks good to me 👍 Sorry the fuss at the beginning, @shethaadit and thank you for handling this!

Let's hear from @BillWagner if there's something to improve.

Thank you @BartoszKlonowski for your suggestions. Appreciate your help and support. :)

Hi @BillWagner, please let me know if this PR looks okay.

[BillWagner]

This looks great. I had one grammar note, and then I'll