Update priority of multiple tasks

I would like to update the priority of multiple existing tasks to the same priority. E.G.
```
tb -p 2 @76 @80
```
After issuing this command the tasks 76 and 80 should have the priority 2.

Right now the command produces the following error.
```
✖ More than one ids were given as input
```

Reproduce the reported command with `tb -p 2 @76 @80` and trace the CLI handling of multiple task IDs and priority updates. Done means both existing tasks receive priority 2 without the “More than one ids were given as input” error, with a regression check for the multi-ID case.

Written by the indexing model from the issue text.