Code is marked up as C++ by default:
// Some C++ code: QWidget *widget = getWidget();
Code can be explicitly marked up as C++ with the Cpp language:
// Some C++ code: QWidget *widget = getWidget();
QML code can be requested with the QML language:
// Some QML code: Item { id: my_item }
Plain text is shown if the text language is used:
// Some C++ code:
QWidget *widget = getWidget();
// Some QML code:
Item {
id: my_item
}