Doc: Fix faulty code snippet in QDeclarativeEngine class reference
Doc: Fix faulty code snippet in QDeclarativeEngine class reference

A common way to access the engine instance is via QDeclarativeView
- fix the code snippet accordingly.

Task-number: QTBUG-20747
Change-Id: Iff837f834ca6c950aa6c78c418f544789b4fcaf9
Reviewed-by: Shawn Rutledge <7b40856c8c1100512025516d7c58756d644d9e8d@digia.com>

kobolabs/qtquick1,kobolabs/qtquick1,kobolabs/qtquick1,kobolabs/qtquick1,kobolabs/qtquick1,kobolabs/qtquick1