Suuport for QML slot functions with signatures (types arguments & return values)

There are currently no tests to check that types slot functions (methods) are correctly processed by doxyqml, which means they are not supported. But they are a thing, so they should.

Example of such a function, from an official Qt documentation:

src/quick/doc/snippets/qml/item/containmentMask-circle-js.qml:

    containmentMask: QtObject {
        property alias radius: circle.radius
        function contains(point: point) : bool {
            return (Math.pow(point.x - radius, 2) + Math.pow(point.y - radius, 2)) < Math.pow(radius, 2)
        }

...which just goes to say that QML syntax is far from being JavaScript as it is.