chore(no-release): fix nested ifdef handling

[KevinEady]

Fix support of nested #ifdef where inner #ifdef / #else / #endif blocks were still being added even if the outer block should have been ignored / excluded.

This PR was merged into my personal fork as KevinEady@9658d86 and created the header sync PR KevinEady#102 :

@@ -17,6 +17,7 @@
 #define NAPI_VERSION 8
 #endif
 
+
 #include "js_native_api_types.h"
 
 // If you need __declspec(dllimport), either include <node_api.h> instead, or

The update script ends up adding an empty line: there is an empty line before the #ifdef and after the #endif, so once removing the #ifdef block, it comes as two lines

// ...
#endif
#endif

#if defined(NAPI_EXPERIMENTAL) &&                                              \
    !defined(NODE_API_EXPERIMENTAL_NO_WARNING) &&                              \
    !defined(NODE_WANT_INTERNALS)
#ifdef _MSC_VER
#pragma message("NAPI_EXPERIMENTAL is enabled. "                               \
                "Experimental features may be unstable.")
#else
#warning "NAPI_EXPERIMENTAL is enabled. " \
       "Experimental features may be unstable."
#endif
#endif

#include "js_native_api_types.h"
// ...

Fixes: #62