Add hint about the timeout unit

[ehrenfeu]

Description Of Changes

Improve user documentation of the timeout parameter by explaining the unit.

Motivation and Context

It took me a while to verify the value actually means seconds and not something else, this should be easy to improve for other users.

Testing

N/A

Operating Systems Testing

N/A

Change Types Made

• Bug fix (non-breaking change).
• Feature / Enhancement (non-breaking change).
• Breaking change (fix or feature that could cause existing functionality to change).
• Documentation changes.
• PowerShell code changes.

Change Checklist

• Requires a change to the documentation.
• Documentation has been updated.
• Tests to cover my changes, have been added.
• All new and existing tests passed?
• PowerShell code changes: PowerShell v2 compatibility checked?

Related Issue

Fixes #138