Help references lucky cli helper even when not using lucky

I'm adding this shard into a project not using lucky. I noticed that a help message references the `lucky` cli command even though this project does not use lucky.

```
❯ crystal tasks.cr
Missing a task name

To see a list of available tasks, run lucky --help
```

I'm not sure what it should say instead, or if this should even be addressed.

Start by reproducing the missing-task-name case with `crystal tasks.cr` in a project that does not use Lucky. Trace where the help message is produced and determine wording that does not assume the `lucky` CLI; done means the message is appropriate for this standalone shard.

Written by the indexing model from the issue text.