When archiving, the preceding task is added in the project field

i.e. from

```
P1:
   - T1
   - T2 @done
```

archiving via `\tD` yields

```
P1:
  - T1
Archive:
  - T2 @done(..) @project(P1 / - T1)
```

But it should be 

```
P1:
  - T1
Archive:
  - T2 @done(..) @project(P1)
```
