WebAssembly qtloader.js onExit is never called

In Qt 6.6.1, the qtloader docs (https://doc.qt.io/qt-6/wasm.html#using-qtloader) include specific mention of "onExit    Callback for when the applicataion exits".  However, this callback is never invoked (see https://bugreports.qt.io/browse/QTBUG-107998 which has been closed as WONTFIX).

The documentation should be updated to remove this hook, and to clearly state that a Qt application can never be cleanly exited by the user (using e.g. QCoreApplication::quit() or similar).  Certainly, I have found no way which allows the user-provided onExit hook to be invoked (perhaps I could invoke it directly using emscripten::val::call but the Qt docs include no example of such that I could find).