QDoc: Discern between C++ and QML versions of a identically-named namespaces

First encountered at https://codereview.qt-project.org/#patch,sidebyside,70541,1,/COMMIT_MSG

When I added

DEPENDS += qtqml

to qtcore.qdocconf, QDoc spewed errors everywhere because it tried to look for C++ types in the "Qt" QML namespace.

UPDATE: 2013-12-29 – Unable to fix some broken links due to this issue
ColorDialog (http://qt-project.org/doc/qt-5/qml-qtquick-dialogs-colordialog.html) has a 'modality' property, of the Qt::WindowModality type (http://qt-project.org/doc/qt-5/qt.html#WindowModality-enum).

Currently, it is impossible to link to Qt::WindowModality, Qt::NonModal, etc. from the ColorDialog documentation, because QDoc searches the QML namespace instead of the C++ namespace and thus fails to find the enum values.