Fix return.missing for strings

Time to get some feedback on these changes.

See 1 more instance in the baseline

$ignoreErrors[] = [
'message' => '#^Function install_download_translation\\(\\) should return string but return statement is missing\\.$#',
'identifier' => 'return.missing',
'count' => 2,
'path' => __DIR__ . '/includes/install.core.inc',
];

If you are another contributor eager to jump in, please allow the previous poster at least 48 hours to respond to feedback first, so they have the opportunity to finish what they started!

I did forget that one. I left it because the @return is incorrect as well but never made back to change it.

Rest looks good!

nod_ → closed merge request !11289

Committed 7735d0e and pushed to 11.x. Thanks!