Fix 'Enforce that an expression gets used' errors

Author: NikolaiProgramist

src/Parser.php

@@ -8,5 +8,5 @@
 function parse(string $pathToFile1, string $pathToFile2, string $format): void
 {
     $resultString = genDiff($pathToFile1, $pathToFile2, $format);
-    line($resultString);
+    line('%s', $resultString);
 }