Disable long option abbreviation (`--destructive` vs `--destructive-mode`)

### What needs to get done

By default, `argparse` allows abbreviated commands, such as `--destructive-mode` being specified as `--destructive`.

Since Python 3.5, this default behavior can be disabled by setting `allow_abbrev=False` when instantiating `argparse.ArgumentParser`:

https://docs.python.org/3/library/argparse.html#allow-abbrev

Found by @thp-canonical and @Ardelean-Calin

### Why it needs to get done

This avoids wrongly learning command-line arguments that might at some point not be unique anymore.