Fix number of parallel lines in output

According to [PSDM](https://powersystemdatamodel.readthedocs.io/en/latest/models/input/grid/line.html)

```
 parallelDevices = overall amount of parallel lines to automatically construct 
(e.g. parallelDevices = 2 will build a total of two lines
using the specified parameters)
```

Thus, our output here should be 1, not 0 ;)