Fatal error Cannot use Drupal\views\ResultRow as ResultRow because the name is already in use

Thanks a lot for reporting and already providing the correct fix!
Generally, no-one should still be using PHP 5 at this point, so it hardly seems worth fixing – but I guess the change still makes sense, and a fatal error is a pretty large problem, even if only a handful of sites will encounter it (I’d guess).
So: committed.
Thanks again!

PS: It seems you (like many others – it's really easy to misinterpret) are confused by the "Issue tags" field. As the guidelines state, they aren't meant for free text tags related to the issue, but only for specific categorization purposes, usually by module maintainers.
So, if you aren't sure your current usage is correct, please just leave the field empty.