NGSTACK-938 fix phpstan issues

Author: JakovKnezovicc

src/Action/CheckLinter.php

@@ -33,7 +33,7 @@ protected function doExecute(Config $config, IO $io, Repository $repository, Act
     }
 
     /**
-     * @param $directories string[]
+     * @param $directories array<string>
      *
      * @return array<string, mixed>
      */

src/Action/CheckPrettier.php

@@ -45,7 +45,10 @@ protected function doExecute(Config $config, IO $io, Repository $repository, Act
 
                 $io->write(sprintf('<info>%s: </info>', $file->getPath()));
 
-                if ($result['success']) {
+                /** @var bool $isResultSuccess */
+                $isResultSuccess = $result['success'];
+
+                if ($isResultSuccess) {
                     $io->write($result['output']);
                 } else {
                     $io->writeError(sprintf('<error>%s</error>', $result['error']));