doc: update windows arm64 build instructions

Updates the build instructions for Windows 10 ARM64, now that cross-compiling on a x64 host is possible.

Refs: nodejs#25998
Refs: nodejs#32582

BUILDING.md

@@ -544,12 +544,12 @@ Optional requirements to build the MSI installer package:
 
 * The [WiX Toolset v3.11](https://wixtoolset.org/releases/) and the
   [Wix Toolset Visual Studio 2019 Extension](https://marketplace.visualstudio.com/items?itemName=WixToolset.WixToolsetVisualStudio2019Extension).
+* The [WiX Toolset v3.14](https://wixtoolset.org/releases/) if building for Windows 10 on ARM (ARM64).
 
 Optional requirements for compiling for Windows 10 on ARM (ARM64):
 
-* ARM64 Windows build machine
-  * Due to a GYP limitation, this is required to run compiled code
-    generation tools (like V8's builtins and mksnapshot tools)
+* ARM64 or x64 Windows build machine
+  * ARM64 builds can be created on a x64 host by running `.\vcbuild arm64`
 * Visual Studio 15.9.0 or newer
 * Visual Studio optional components
   * Visual C++ compilers and libraries for ARM64