cannot open source file "WProgram.h" in VSCode
I landed here in the same position as you, and after researching the comments mentioning -DARDUINO=10813 and some more googling I found: https://github.com/microsoft/vscode-arduino/issues/1148
This led me to adding one more line to defines in my c_cpp_properties.json
and this also removed the squiggly!
{
    &quot;configurations&quot;: [
        {

            ...

            &quot;defines&quot;: [
                &quot;USBCON&quot;,
                &quot;ARDUINO=10813&quot;
            ],

            ...

        }
    ],

}```