RE: option doc strings and Customize tags

[Drew Adams]

>  >  nil      Case-sensitive
>  >  t        Case-insensitive
>  >  <other>  Use default
> 
> I'd put the Lisp values in parentheses as
> 
>      Case-sensitive (nil)
>      Case-insensitive (t)
>      Use default

Sure, fine, whatever. It doesn't matter much what format we use. Except that
adding parens might confuse things for Lisp values that are lists: ((foo bar)).

A more general formatting problem is that the Lisp values might be quite long.
Some kind of abbreviation is probably called for. And we still need something to
indicate `other value'.