style(bash): out is not an array variable, do not refer to it as such (#1684)

For legacy bash completions, similarly as commit
4f0facbcee0aadb87179d3fed80e92709de491a9 is for bash completions v2.

As a side effect, fixes test suite with shellcheck 0.8.0 installed;
apparently the 0.7.0 that's in GitHub Actions' ubuntu-latest at the
moment does not flag the array quoting related issue that was provoked
from 0.8.0 before this change.