Update Documentation For cmd.run regarding Windows runas argument

[JacobSweeten]

The following code snippet is the only place where there is any mention of using the password field:

salt/salt/states/cmd.py

Lines 869 to 873 in 53cc103

	runas
	Specify an alternate user to run the command. The default
	behavior is to run as the user under which Salt is running. If running
	on a Windows minion you must also use the ``password`` argument, and
	the target user account must be in the Administrators group.

The documentation should warn of this as well.

Also, the error that I get when this is omitted (On 2019.2) is "embedded null character". There should be better error detection for a lack of password input on Windows.

The state code to reproduce the issue is relatively simple:

   cmd.run:
    - name: |
        my commands here
    - shell: powershell
    - runas: Administrator

[sagetherage]

@JacobSweeten this looks like two issues, yes? One to update the docs and one to make the error message be more descriptive. Separating them into two issues/tickets, as I may have one person work on each piece, but would want them linked for referencing and testing. Let me know if you see a problem with that process.

[sagetherage]

great, here is the error message issue: #57951