dig: Support multiple domains in a single lookup (#6334)
* dig: Support multiple domains in a single lookup (#6334)
The docs for this plugin indicated that multiple domains could be
specified at once, but the code did not support multiple domains.
* Address review feedback.
(cherry picked from commit 64e797d077)
Co-authored-by: Kevin P. Fleming <kpfleming@users.noreply.github.com>
