WindowsCore: add definition for MAKEWORD

[compnerd]

This is a complex function-like macro that concatenates to bytes. The complexity stems in the extensive type-casting. Provide a Swift implementation for this macro.

[Copilot]

Pull Request Overview

This PR adds a Swift implementation of the Windows MAKEWORD macro to the WindowsCore module. The macro concatenates two bytes into a 16-bit word by placing the high byte in the upper 8 bits and the low byte in the lower 8 bits.

• Adds MAKEWORD function that combines two BYTE parameters into a WORD

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