bug#25482: 26.0.50; Allow setting `query-replace-from-to-separator` to nil

[Thierry Volpiatto]

Eli Zaretskii <eliz@gnu.org> writes:

> I'm asking whether the (fixed) behavior, whereby using setq to change
> the value to " -> " would add the ASCII string " -> " to the
> minibuffer history, would be acceptable.  If not, please tell why.

Would be good, but we will have to modify also
`query-replace--split-string` just for this purpose as it assume the
separator is one char long and have a text property 'separator.

I wanted to keep things as simple as possible in this patch.

-- 
Thierry