LocalFree should be take void* or IntPtr as its parameter

[AArnott]

Actual behavior

The LocalFree method is declared by CsWin32 as taking an nint:

[DllImport("KERNEL32.dll", ExactSpelling = true, SetLastError = true)]
[DefaultDllImportSearchPaths(DllImportSearchPath.System32)]
internal static extern nint LocalFree(nint hMem);

Expected behavior

The method takes a pointer. Not an arbitrary pointer-sized integer. While this is just semantics, it is more intuitive to use IntPtr or (even better) void* for the parameter type.
As it is, I have to cast pointers to nint to call this method.

Same for the return type.

[AArnott]

Blocked by microsoft/win32metadata#1296

[AArnott]

Fixed in #889