bug#45764: icomplete in buffer completion does not work for completion-at-point

[Juri Linkov]

close 45764 30.0.50
thanks

>> `C-j' is bound to `icomplete-force-complete-and-exit', and it calls
>> `minibuffer-force-complete-and-exit' unconditionally, which deletes the
>> buffer contents.
>
> There are 2 problems, both of which stem from the fact that the code has
> not been adjusted to the case where it's working in a normal buffer
> rather than in the minibuffer:
> - it calls `minibuffer-exit` which is wrong for in-buffer completion
>   (it should probably exit `completion-in-region-mode` instead).
> - it assumes the area of completion is the whole buffer (it should
>   probably use `icomplete--field-end/beg`).

This is fixed now in master, and with these fixes works quite nicely.