bug#114: Shell-mode: File completion breaks editing previous commands

[Glenn Morris]

Stefan Monnier wrote:

> Maybe the best fix is to get rid of this `input' field value (the rest
> of the text already gets an `output' field value, so a nil value would
> still work as a field).
>
> E.g. the patch below seemed to fix the problem, but I'm not sure what
> other consequences it might have.

For one, it leaves the help echo ("mouse-2: insert after prompt as new
input") and mouse highlight properties broken in two on either side of
the portion inserted by completion.