Another minor thing

[Miles Bader]

that I'd like to fix post 20.1 is to make the cursor positioning
relative to overlay before/after-strings reflect where inserted text
will actually go.

Currently, the cursor *always* follows before/after-strings, even if the
corresponding overlay end-point will move upon insertion; this has the
odd effect that typing at such a point results in the newly inserted
text appearing somewhere distant from the cursor.  I'd like to change it
so that the cursor's position will reflect the insertion type of the
appropriate overlay end-point.

I looked at the relevent code, and I don't think this is too hard to
fix, but will necessitate keeping a bit more state around in some
places.

Does this seem the right thing to do?

-Miles
-- 
Love is a snowmobile racing across the tundra.  Suddenly it flips over,
pinning you underneath.  At night the ice weasels come.  --Nietzsche