Write DX version in dx_settings for easier troubleshooting

[carlmylo]

Not sure how possible this would be but it would be a nice thing to have for people trying to help troubleshoot others' issues.
This is mostly as I've stumbled onto a few people that have disabled the title screen and are online, meaning there's no way to easily get their DX version.

If there's a better method, that'd be fine too.