bug#34311: Rapid toggling of Overwrite mode never makes sense

[積丹尼 Dan Jacobson]

Hold down the "Insert" key on your keyboard.

Overwrite mode enabled in current buffer
Overwrite mode disabled in current buffer
Overwrite mode enabled in current buffer
Overwrite mode disabled in current buffer

at a rather fierce pace, that would never make sense.
(Unlike holding down "_" to make:
"Please sign here _________________".)

Anyway in such cases the user surely never intended to toggle Overwrite
mode in the first place, and just accidentally touched it.

And in half the cases he has now accidentally left it on, until he
discovers it.

Yes the user can disable the function.

But I'm just pointing out that maybe there should be some (railroad)
brakes attached, maybe any toggling faster than one per second should
raise a beep or two. Thanks.