Do not crash on invalid UTF-8

Author: ondrejmirtes

Diff for: src/Parser/ParserException.php

@@ -7,6 +7,7 @@
 use function assert;
 use function json_encode;
 use function sprintf;
+use const JSON_INVALID_UTF8_SUBSTITUTE;
 use const JSON_UNESCAPED_SLASHES;
 use const JSON_UNESCAPED_UNICODE;
 
@@ -84,7 +85,7 @@ public function getExpectedTokenValue(): ?string
 
 	private function formatValue(string $value): string
 	{
-		$json = json_encode($value, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
+		$json = json_encode($value, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES | JSON_INVALID_UTF8_SUBSTITUTE);
 		assert($json !== false);
 
 		return $json;