Add new game message hint

[Diordany]

The new game message didn't give a hint as to which button should be pressed to confirm or cancel. This message has been present since the original release by id software, and I thought it helped to simply add "y/n" at the end of the message for anyone who isn't familiar with how the modal message works.

[alexey-lysiuk]

Other modal messages use (y/n) instead of just y/n.

Also, please avoid white-space only changes. It should be only one line modified instead of four.

[Diordany]

Yes sorry about that @alexey-lysiuk, my IDE's editor automatically changed the other lines. I'll take care of it.

Also, do you want me to change y/n to (y/n) instead?

[alexey-lysiuk]

Also, do you want me to change y/n to (y/n) instead?

Let's wait for another opinion. For me, it should match with the rest of SCR_ModalMessage() calls.

[Diordany]

Let's wait for another opinion. For me, it should match with the rest of SCR_ModalMessage() calls.

Alright, got it.

[sezero]

Also, do you want me to change y/n to (y/n) instead?

That would be good, yes.

[sezero]

And: squash the commits into a single one, please.

[Diordany]

I've made the changes @sezero.

[sezero]

OK, this is in. Thanks.