Improve VB error reference TOC scannability by using error codes and specific error types

[Copilot]

This PR improves the scannability of the Visual Basic error messages table of contents by replacing long descriptive error message names with concise error codes and specific error type designations.

Problem

The VB error messages TOC used lengthy descriptive names that made it difficult to quickly scan and locate specific errors, and had duplicate "Runtime error" entries without numeric codes.

Changes Made

• Traditional VB Runtime Errors: Added specific numeric codes (e.g., "Runtime Error 322", "Runtime Error 449", "Runtime Error 440")
• Application Framework Errors: Replaced generic "Runtime error" entries with specific error types:
  • "Application startup error" for VB.NET application framework startup issues
  • "File I/O error" for .NET file system operation errors
• Eliminated Duplicates: Removed duplicate generic "Runtime error" entries that lacked proper identification

This approach distinguishes between traditional VB6-style numbered runtime errors and modern .NET application framework errors, improving both scannability and accuracy while eliminating confusion from duplicate entries.

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Internal previews

📄 File	🔗 Preview link
docs/visual-basic/toc.yml	docs/visual-basic/toc

[BillWagner]

This LGTM.

This is ready for final review.