Parsing JSON at compile time with C++26 static reflection

This is basically a demo for simdjson's static reflection feature:

> Recent versions of simdjson can parse JSON at compile time using C++26 static reflection. The entry point is simdjson::compile_time::parse_json

Requires language support, for example using gcc 16. Impressive feature!

    #define SIMDJSON_STATIC_REFLECTION 1
    #include "simdjson.h"
    constexpr const char json_data[] = {
        #embed "data.json"
        , 0
    };
    constexpr auto window = simdjson::compile_time::parse_json<json_data>();