I've checked in another installment of my incremental cleanup of the 
attribute documention in extend.texi.  Here I've moved the sections on 
variable and type attributes to immediately follow the function 
attributes section, instead of having a bunch of sections on other 
features randomly dropped in between.  There are no changes to the 
actual content here, just the section ordering.

I mentioned a couple months ago that I thought this whole chapter needed 
to be organized better.  I'm not tackling that project yet, but at least 
it is a start to group these clearly related sections together.

-Sandra