bug#70968: 29.2.50; choose-completion on an emacs22-style completion deletes text after point

[Spencer Baugh]

Here is an idea:

Currently emacs22 is the only style that ignores the text after point
when completing.  But, this is often useful behavior, and I'd like to
support it in other completion styles as a fallback.  Specifically, I
think it would be nice if completion always:

1. Try to complete including the suffix after point (like the basic,
partial-completion, substring styles do)

2. If no completion matches, try to complete again without the suffix
after point

What if we implemented this in the completion machinery itself?  If no
style matches, run through all the styles again without the suffix after
point.  This would allow e.g. partial-completion behavior when
completing in the middle of a symbol, which currently doesn't work.

This would basically remove the emacs22 style, since it would be a
behavior implemented at a higher level.  Then each completion frontend
could implement this "first with suffix then without suffix" behavior
separately, which would make choose-completion and similar calls easier
to make work.

Stefan, I wonder if you have thoughts on this idea?