Add CreateTestClass/DeleteTestClass P/Invoke declarations to marshalling docs snippet

[Copilot]

CreateTestClass and DeleteTestClass were defined in PInvokeLib.h but absent from the managed P/Invoke declarations, leaving the documentation without coverage of how to marshal foreign heap-allocated C++ class pointers.

Changes

• C# (NativeMethods.cs): Added both declarations using unsafe void* to represent the opaque CTestClass*:

[DllImport("PinvokeLib.dll", CallingConvention = CallingConvention.Cdecl)]
internal static extern unsafe void* CreateTestClass();

[DllImport("PinvokeLib.dll", CallingConvention = CallingConvention.Cdecl)]
internal static extern unsafe void DeleteTestClass(void* instance);

• VB (NativeMethods.vb): Added equivalent declarations using IntPtr (VB has no void*):

<DllImport("PinvokeLib.dll", CallingConvention:=CallingConvention.Cdecl)>
Friend Shared Function CreateTestClass() As IntPtr
End Function

<DllImport("PinvokeLib.dll", CallingConvention:=CallingConvention.Cdecl)>
Friend Shared Sub DeleteTestClass(ByVal instance As IntPtr)
End Sub

Both declarations fall inside the existing <NativeMethods> snippet markers, so they surface automatically in the "Managed function prototypes" section of the published article.

• Fixes Marshalling Data with P/Invoke: missing examples using CreateTestClass/DestroyTestClass #54833

[Copilot]

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[jkoritzinsky]

@copilot please add AllowUnsafeBlocks=true to the corresponding csproj for the C# code if it isn't already present

[Copilot]

@copilot please add AllowUnsafeBlocks=true to the corresponding csproj for the C# code if it isn't already present

Added <AllowUnsafeBlocks>true</AllowUnsafeBlocks> to PInvokeLibManaged.csproj in commit 1e26bc2.