Better command debuggin

Signed-off-by: Joas Schilling <coding@schilljs.com>

lib/Chat/Command/Executor.php

@@ -198,7 +198,7 @@ class Executor {
 			);
 		} catch (\InvalidArgumentException $e) {
 			$this->logger->logException($e);
-			return '';
+			return $this->l->t('An error occurred while running the command. Please ask an administrator to check the logs.');
 		}
 	}
 }

lib/Chat/Command/ShellExecutor.php

@@ -103,7 +103,7 @@ class ShellExecutor {
 		@exec($cmd, $output, $returnCode);
 
 		if ($returnCode) {
-			throw new \InvalidArgumentException('Chat command failed with return code: ' . $returnCode);
+			throw new \InvalidArgumentException('Chat command failed [Code: ' . $returnCode . ']: ' . $cmd);
 		}
 
 		return implode("\n", $output);