bug#55810: 28.1; No "really edit the buffer?" prompt when editing a changed file over Tramp

[Jim Porter]

To see this in action:

  $ cat file.txt
  hi

  $ emacs -Q
  C-x C-f /ssh:localhost:~/file.txt

  $ echo bye >> file.txt

Back in Emacs, type anything into the buffer. It should ask, "file.txt 
changed on disk; really edit the buffer?" However, it doesn't. (It does 
still provide a warning you when you save though.)

Note: this used to work in Emacs 27, and works again in Emacs 29, but 
Emacs 28 fails.

Strangely, I updated Tramp from GNU ELPA and the bug went away, but only 
until I restarted Emacs; then it returned. I haven't had time to try and 
reliably reproduce this part though, so that might just be a coincidence.