Update src/Smalot/PdfParser/PDFObject.php

Use strict false check.

Co-authored-by: Konrad Abicht <hi@inspirito.de>

src/Smalot/PdfParser/PDFObject.php

@@ -220,7 +220,7 @@ private function formatContent(?string $content): string
         // indicates the beginning of a string. Then test what remains
         // for valid UTF-8. If it's not UTF-8, return an empty string
         // as this $content is most likely binary.
-        if (!mb_check_encoding(preg_replace('/\(.*$/s', '', $content), 'UTF-8')) {
+        if (false === mb_check_encoding(preg_replace('/\(.*$/s', '', $content), 'UTF-8')) {
             return '';
         }