No wrap-around of conflicting &mnemonic key in QtQuick.Controls 2 Menu

Unlike platform menu or QMenu of QWidget, &mnemonic key in Controls 2 Menu doesn't wrap around.

For example, pressing Alt+D+D+D+... doesn't move the current item inside the menu, but
flips the visibility of the menu.

        Menu {
            title: qsTr("&Debug")
            Action { text: qsTr("&Do it") }
            Action { text: qsTr("&Do it") }
            Action { text: qsTr("&Do it") }
        }

I understand QtQuick.Controls doesn't try to copy the platform's exact behavior, but I think
it's common for menu to have ambiguous &mnemonic items.

The wrapping behavior could be implemented without modifying Qt codebase, but
it wasn't an easy task. For reference, my PoC-level hack is attached.