Issue #1276: cleanup wrong-arg-num err msg on 0-arg tasks

0 arg task arglist was printing as `""` since passing `[project]` to
`next` resulted in `nil` which prints as `""`. Used `(comp vec next)`
instead to force it into `[]` which prints as `"[]"`.
Merge pull request #1278 from fredericksgary/issue-1276

Issue #1276: cleanup wrong-arg-num err msg on 0-arg tasks