Several 'framework' fixes

src/Puzzle.php

@@ -17,6 +17,9 @@ class Puzzle extends Command
             ->addArgument('day', InputArgument::REQUIRED, 'The day number.');
     }
 
+    /**
+     * @return int
+     */
     protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $contents = file_get_contents(sprintf('%s/../data/day%s/puzzle.md', __DIR__, (int) $input->getArgument('day')));