Two minor hacks for Playground that I can't be bothered to do properly, to match desired spec

- Play intro when exiting goner Playground
- Do not allow using menu to skip driving down that hill in goner Playground
The reason these two are hacks is because a map is considered goner Playground if you use -warp at command line or map in console on title screen to get to a Tutorial course... but these are unimportant edge cases IMO

src/g_game.c

@@ -5130,6 +5130,13 @@ void G_EndGame(void)
 		return;
 	}
 
+	if (gametype == GT_TUTORIAL && M_GameTrulyStarted() && restoreMenu == NULL) 
+	{
+		 // Playground Hack
+		F_StartIntro();
+		return;
+	}
+
 	// Time to return to the menu.
 	Command_ExitGame_f();
 }

src/menus/transient/pause-game.c

@@ -561,7 +561,8 @@ void M_EndGame(INT32 choice)
 	if (!Playing())
 		return;
 
-	if (M_GameTrulyStarted() == false)
+	if (M_GameTrulyStarted() == false
+	|| (gametype == GT_TUTORIAL && restoreMenu == NULL)) // Playground Hack
 	{
 		// No returning to the title screen.
 		M_QuitSRB2(-1);