Doc: Fix qmlclass selector used in documentation config

A recent change (46959875) in qdoc raised QML types from
subnodes to top-level nodes. This change modifies the
documentation configuration file(s) accordingly.

Change-Id: I42fe45b82e8342ddbd535c79754c1eea29521391
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>
Reviewed-by: Martin Smith <martin.smith@digia.com>