LoggingCategory documentation encourages the use of a singleton without explaining how

https://doc.qt.io/qt-5/qml-qtqml-loggingcategory.html says:

Note: As the creation of objects is expensive, it is encouraged to put the needed LoggingCategory definitions into a singleton and import this where needed.

New users might have no idea how to do this. We should have an example that demonstrates how such a singleton would look. For example:

pragma Singleton

import QtQml 2.12

QtObject {
    property LoggingCategory dialogs: LoggingCategory {
        name: "app.ui.dialogs"
    }
    
    property LoggingCategory settings: LoggingCategory {
        name: "app.settings"
    }
}

and then link to the documentation that describes how the qmldir should look, etc.