Fields::getDetails() can return a TranslatableMarkup object

Problem/Motivation

We get this error when running "drush security:review":

 [error]  TypeError: Drupal\security_review\Plugin\SecurityCheck\Fields::getDetails(): Return value must be of type array|string, Drupal\Core\StringTranslation\TranslatableMarkup returned in Drupal\security_review\Plugin\SecurityCheck\Fields->getDetails() (line 338 of /var/www/web/modules/contrib/security_review/src/Plugin/SecurityCheck/Fields.php) #0 /var/www/web/modules/contrib/security_review/src/Commands/SecurityReviewCommands.php(238): Drupal\security_review\Plugin\SecurityCheck\Fields->getDetails(Array, Array, true)
#1 /var/www/web/modules/contrib/security_review/src/Commands/SecurityReviewCommands.php(192): Drupal\security_review\Commands\SecurityReviewCommands->formatResults(Array, false, true)
#2 [internal function]: Drupal\security_review\Commands\SecurityReviewCommands->securityReview(Array)
#3 /var/www/vendor/consolidation/annotated-command/src/CommandProcessor.php(276): call_user_func_array(Array, Array)
#4 /var/www/vendor/consolidation/annotated-command/src/CommandProcessor.php(212): Consolidation\AnnotatedCommand\CommandProcessor->runCommandCallback(Array, Object(Consolidation\AnnotatedCommand\CommandData))
#5 /var/www/vendor/consolidation/annotated-command/src/CommandProcessor.php(175): Consolidation\AnnotatedCommand\CommandProcessor->validateRunAndAlter(Array, Array, Object(Consolidation\AnnotatedCommand\CommandData))
#6 /var/www/vendor/consolidation/annotated-command/src/AnnotatedCommand.php(387): Consolidation\AnnotatedCommand\CommandProcessor->process(Object(Symfony\Component\Console\Output\ConsoleOutput), Array, Array, Object(Consolidation\AnnotatedCommand\CommandData))
#7 /var/www/vendor/symfony/console/Command/Command.php(279): Consolidation\AnnotatedCommand\AnnotatedCommand->execute(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#8 /var/www/vendor/symfony/console/Application.php(1094): Symfony\Component\Console\Command\Command->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#9 /var/www/vendor/symfony/console/Application.php(342): Symfony\Component\Console\Application->doRunCommand(Object(Consolidation\AnnotatedCommand\AnnotatedCommand), Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#10 /var/www/vendor/symfony/console/Application.php(193): Symfony\Component\Console\Application->doRun(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#11 /var/www/vendor/drush/drush/src/Runtime/Runtime.php(110): Symfony\Component\Console\Application->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#12 /var/www/vendor/drush/drush/src/Runtime/Runtime.php(40): Drush\Runtime\Runtime->doRun(Array, Object(Symfony\Component\Console\Output\ConsoleOutput))
#13 /var/www/vendor/drush/drush/drush.php(140): Drush\Runtime\Runtime->run(Array)
#14 /var/www/vendor/bin/drush.php(119): include('/var/www/vendor...')
#15 {main}. 

Steps to reproduce

Proposed resolution

Fields::getDetails() should either cast the return value to a string or add TranslatableMarkup to the return type hint.

Remaining tasks

User interface changes

API changes

Data model changes