No notifications when changing diskette for Famicom Disk System

[KamiLordus]

Please add text notifications when changing a diskette for the Famicon Disk system. Without text notifications, it is difficult to change a diskette and easy to make a mistake. This is how it looks in the case of the FCEUmm core:

[carmiker]

Yes, this is a needed improvement. The FDS disk switching is generally dodgy and needs some work.