CategoryModel is unintuitive

The example given at http://doc.qt.io/qt-5/qml-qtlocation-categorymodel.html#details will not display anything by default. Instead, the update() method must be called (e.g. Component.onCompleted: update() must be added to the CategoryModel). This is unintuitive, and undocumented.

Ideally, update() should not need to be called in this simple usecase (note: it appears this behavior was introduced in 72dd61d45aa05512d66eb154df150cb20b35ba8f). If it isn't possible to improve, this behavior should at minimum be documented.