Document AbstractFeedback bit more.
Document AbstractFeedback bit more.

RevBy: Michael Hasselmann

This work was done by Openismus GmbH for Canonical Ltd

RHawkeyed/plugins,maliit/plugins,KDE/plasma-maliit-plugins,KDE/plasma-maliit-plugins,develersrl/maliit-demo-qml,develersrl/maliit-demo-qml,KDE/plasma-maliit-plugins,RHawkeyed/plugins,KDE/plasma-maliit-plugins,maliit/plugins,RHawkeyed/plugins,maliit/plugins,maliit/plugins,RHawkeyed/plugins,RHawkeyed/plugins,develersrl/maliit-demo-qml,develersrl/maliit-demo-qml