QML auto format rewrites computed property names

Context: there exists a very useful feature in javascript called computed property names, this appears to be supported in Qt QML.

The following example won't run, but it does demonstrate the problem

```QML

// Example usage

Item {
    property var exampleMapping: (

{         [someObject.property]: "I am an example",         // ...     }

)
}

// after auto formatting:
Item {
    property var exampleMapping: (

{         "someObject.property": "I am an example",         // ...     }

)
}

```

The auto-formatter is incorrectly changing the property to a string. Equally if you just use a local variable the formatter will replace the computed property with a string