Doc: Update Qt Quick Controls description
Doc: Update Qt Quick Controls description

Change-Id: Idd056eea674a96236656c452e7a1df5e8e20f0fd
Reviewed-by: Jerome Pasion <c10995d24f6b454503389e8d00d837aef038985d@digia.com>

kobolabs/qtdoc,kobolabs/qtdoc,kobolabs/qtdoc,kobolabs/qtdoc