bug#61943: 29.0.60; icomplete--in-region-setup should activate icomplete-fido-mode-map too

[Juri Linkov]

>> fido-vertical mode and/or icomplete-vertical-mode needs more work
>> to support in-buffer completions, please decide whether to revert it
>> or to write an additional patch for these modes in emacs-29.
>
> OK, I'll revert just the fido-mode-specific patch in emacs-29. But are
> you sure that icomplete-in-buffer works consistently for icomplete-mode?
> If it doesn't it'll need more changes, and -- crucially -- changes that
> don't break other icomplete cousins like fido and vertical modes.
> If it does work OK, then no problem.

icomplete-in-buffer works consistently in all my tests.
But maybe Sean will show more recipes if there are more problems.