bug#61310: Eshell modifying and running output regression

[Morgan Smith]

Hello,

eshell allows you to modify the output of a command and run it.  It is a
beautiful thing.

Example:

$ ls
file.el
$

now go up and append "file" to the output and hit enter.

$ ls
file file.el
$ file file.el
color.el: Lisp/Scheme program, Unicode text, UTF-8 text
$


The ability is currently broken because "file.el" has the field property
set to "command-output" and the "file" command that I added has no
property field.  So currently the previous interaction would actually
yield:

$ ls
file file.el
$ file.el
file.el: command not found
$


This was broken in commit 558f04c39e036d2f681f72556627768d7bee9ab5.  Now
adding the field to eshell prompt makes a lot of sense and I like that.
I don't know much about fields but it looks like it is not necessary to
have a command-output field at all.  I propose we get rid of that.  If
you want to keep the field, can we make it sticky or something?  I just
want the above usecase fixed.


Thanks,

Morgan