LibJS: Make ParserError::to_string infallible

Author: https://github.com/shannonbooth
Commit: 0090b916dd
Pull-request: https://github.com/SerenityOS/serenity/pull/23817
Reviewed-by: https://github.com/ADKaster
Reviewed-by: https://github.com/trflynn89

Userland/Libraries/LibJS/ParserError.h

@@ -19,7 +19,7 @@ struct ParserError {
     ByteString message;
     Optional<Position> position;
 
-    ErrorOr<String> to_string() const;
+    String to_string() const;
     ByteString to_byte_string() const;
     ByteString source_location_hint(StringView source, char const spacer = ' ', char const indicator = '^') const;
 };