qdoc: sort qml methods by name

The method name, not the return value type, should be used for sorting QML methods. For example, Item's methods:

• childAt(real x, real y)
• forceActiveFocus()
• object contains(point point)
• object mapFromItem(Item item, real x, real y)
• ...

Should be:

• childAt(real x, real y)
• object contains(point point)
• forceActiveFocus()
• object mapFromItem(Item item, real x, real y)
• ...