bug#50459: 28.0.50; Python shell completion is incompatible with flex, orderless, etc.

[Gregory Heytings]

> > The issue lies in the fancier completion styles, which always send the 
> > empty string as the STRING argument to any completion table.
>
> FTR, a similar issue has been discussed recently for remote file names 
> in bug#50387.

Absolutely not.  With (add-to-list 'completion-styles 'substring) or 
(add-to-list 'completion-styles 'flex), completion works as expected in 
Python shells, and not in Tramp.