bug#18246: enriched-encode: should set inhibit-point-motion-hooks, too

[Eli Zaretskii]

> Date: Mon, 11 Aug 2014 23:15:28 -0400
> From: Richard Stallman <rms@gnu.org>
> Cc: ivan@siamics.net, 18246@debbugs.gnu.org
> 
> Whatever problems `intangible' may have, we need some such feature
> to make it convenient to set up forms for the user to fill in.

We can do that without `intangible': just use display properties or
overlays for the parts where you don't want the cursor to enter.  The
default behavior for point motions with text that comes from display
properties or overlay strings is to skip such text.