Add strict types, add debug info

app/Exceptions/BadHttpHeaderException.php

@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace FireflyIII\Exceptions;
 
@@ -10,4 +11,4 @@ use Exception;
 class BadHttpHeaderException extends Exception
 {
     public int $statusCode = 406;
-}
+}