RE: Exposing Isearch toggleable options

[Drew Adams]

> > Artur, does this mean the I-search prompt would be two-lines high in the
> > minibuffer, instead of one-line? If so, I would definitely want a way to
> > disable it; if I already know the options, it shortens the text window for
> > documentation I wouldn't need.
> 
> How about showing that on the mode line, like we do for eldoc-mode?

There are many Isearch bindings, some of which are (far) more
important than toggles.  Why promote these particular bindings
in this way?

Why not encourage users to consult the Isearch help?
 And have that help explicitly describe the available toggles,
     as well as the most important keys.
 And have that help list _all_ of the Isearch key bindings,
     at the end.
 And provide that help on a quick Isearch key (e.g. `C-h').

It is misguided, IMHO, to privilege this kind of thing, either
at Isearch startup (a message) or in the mode line.

Messages should be used for changes of state.
Mode-line indications should be used for the current state.