Fix BitConverter.ToUInt128 documentation inconsistency

[Copilot]

The documentation for BitConverter.ToUInt128(byte[] value, int startIndex) contained an inconsistency:

• Summary: incorrectly stated "four bytes"
• Returns: correctly stated "sixteen bytes"

Since UInt128 is a 128-bit integer, it requires 16 bytes (128 ÷ 8 = 16), not 4 bytes. This fix updates the summary to correctly state "sixteen bytes" to match the returns documentation and the actual implementation.

Before:

/// <summary>
/// Returns a 128-bit unsigned integer converted from four bytes at a specified position in a byte array.
/// </summary>

After:

/// <summary>
/// Returns a 128-bit unsigned integer converted from sixteen bytes at a specified position in a byte array.
/// </summary>

The change aligns with:

• The actual implementation (UInt128.Size = 16)
• The returns documentation (which correctly states "sixteen bytes")
• The consistent documentation in ToInt128 method

Fixes #117364.

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.

[skyoxZ]

There are more four bytes comments problems in BitConverter.cs. Can @copilot fix them all?

[stephentoub]

There are more four bytes comments problems in BitConverter.cs. Can @copilot fix them all?

Yes, @copilot, please find and fix all such issues.

[Copilot]

There are more four bytes comments problems in BitConverter.cs. Can @copilot fix them all?

Yes, @copilot, please find and fix all such issues.

Fixed all "four bytes" documentation inconsistencies in BitConverter.cs. Updated ToUInt64 and ToDouble documentation to correctly state "eight bytes" (64-bit types). The previously fixed ToUInt128 and all remaining "four bytes" references for 32-bit types are now consistent. Changes committed in 6c874d8.