bug#9727: 24.0.90; Lazy highlighting in _word_ Isearch

[Juri Linkov]

> From "emacs -Q":
> 1. Type "M-<" (to move point to the beginning of *scratch* buffer).
> 2. Type "C-s is" (to search for "is").
> 3. Type "M-s w" (to switch to word-type Isearch).
> --> (Expected) Only the _word_ "is" gets lazy-highlighted.
> --> (Observed) The lazy highlighting remains in each "is" (as before
> step #3), regardless of whether it's a word by itself or not.

Thanks for noticing this.  Now fixed.