bug#31807: 27.0; `info-apropos' bad name or bad matching

[Drew Adams]

> > Did you present the same, we-can't-enhance-because-legacy
> > argument when Kim (I think it was) added keyword-matching
> > to the `apropos*' commands?
> 
> That change was backward-compatible.

No more so than this one, IMO.  In fact less.

If you entered "foo bar" (without the quotes) before that
enhancement the commands would try to match only that literal
string (as a regexp).  After the enhancement, entering that
same text caused matching against a complex regexp that
matches "foo" (no space) and "bar" (no space) in either order.
Not at all the same behavior.

This change is more backward compatible.  If you enter "foo"
or "(foo)" or "%foo" you still get the same behavior.  The
only change in behavior occurs if you include regexp special
chars.