[AC21.5] Simplify redisplay-x/separate_textual_runs

[Stephen J. Turnbull]

APPROVE COMMIT 21.5

Stephen J. Turnbull writes:
 > Olivier Galibert writes:
 >  > On Sun, Apr 01, 2007 at 11:53:12PM +0900, Stephen J. Turnbull wrote:

 >  > > Also, I'd like to suggest the patch below (to be applied *on top of*
 >  > > your patch).
 > 
 >  > I like it.
 > 
 > OK, I think you can apply your patch, and once I've negotiated some
 > wording with Aidan, I plan to apply mine.

I've updated the comments somewhat per discussion with Aidan (he
basically said "do what you want", so he's not responsible for the
final wording), and done separate commits of OG's patch (he's
currently commit-challenged), then mine.

Thanks to Mike and Aidan for reviews.