Change Details

- just like in `fileNameChanged()` call `updateContent()` in `fileTypeChanged()` if necessary - put those calls in an extra function/slot

- just like in `fileNameChanged()` call `updateContent()` in `fileTypeChanged()` if necessary - put those calls in an extra function

- just like in `fileNameChanged()` call `updateContent()` in `fileTypeChanged()` if necessary - put those calls in an extra function/slot