bug#22494: still can't search for two spaces

[Drew Adams <drew.adams@oracle.com>]

> > This is a bug. When the user types SPC SPC in a search string, person
> > clearly wants to search for two spaces. It should do that.
> 
> Yes, exactly in the same sense that we disable case folding if mixed case is
> used in a search string.

1. We do both, yes.  But I see no logical connection between those
two design decisions.  Neither of them implies or supports the other.

2. Here's another consideration that might apply to whether we
automatically switch to literal whitespace search due to multiple,
contiguous whitespace chars (and yes, you could argue similarly wrt
automatic turn-off of case-folding):

If a user _types_ additional whitespace chars then it is
reasonable to assume that literal search is what is intended.

But if a user _pastes_ some copied text that includes multiple,
contiguous whitespace chars, then such an assumption is less
reasonable.

The intention might depend on where the text was copied from, etc.
It's really hard to guess whether the user intended to respect the
copied whitespace literally - or even whether s?he is aware that
there are multiple, contiguous whitespace chars in the pasted text.