Add guidance on identifying conflicting assemblies in CS0433 compiler error documentation

[Copilot]

This PR addresses a user's difficulty in identifying which assemblies are causing CS0433 compiler errors. The issue was that while the error message contains the assembly information, users weren't sure how to extract this information from the error message format.

Changes Made

Added a new section "How to identify the conflicting assemblies" to the CS0433 documentation that:

• Explains the error message format with a concrete example
• Shows how assembly names appear in single quotes before version information
• Provides actionable guidance on using the assembly names to resolve conflicts

Example

The new section shows users how to read error messages like:

error CS0433: The type 'N.C' exists in both 'A, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' and 'B, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null'

And explains that the conflicting assemblies are A and B (the names in single quotes).

Validation

• ✅ Passes markdown linting with zero errors
• ✅ Follows Microsoft Writing Style Guide (sentence case, active voice, present tense, imperative mood)
• ✅ Minimal change that doesn't modify existing working content
• ✅ Directly addresses the user's troubleshooting need

Fixes #27598.

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Internal previews

📄 File	🔗 Preview link
docs/csharp/language-reference/compiler-messages/cs0433.md	docs/csharp/language-reference/compiler-messages/cs0433

[BillWagner]

This LGTM.

I'll mark it ready for final review.