bug#7503: copy-and-insert-previous-line

[Stefan Monnier]

> There is a difference between my version, and this one, as mine doesn't
> add the newline-character from the end of the previous line.

I think such differences is the reason why such commands are not very
good candidates for inclusion in Emacs: there are so many different
commands that do something along these lines, that adding them all would
not make much sense.
Luckily, we do have two generic solutions for it:
- you can define it in Elisp as you've done.
- you can define it as a macro.


        Stefan