Summary of the new feature / enhancement

The lack of milliseconds as a parameter to New-Timespan seems like a needless omission from the parameter set.

Please could we add it, I assume it is an easy one

Proposed technical implementation details (optional)

Add a new parameter

    /// <summary>
    /// Allows the user to override the millisecond.
    /// </summary>
    [Parameter(ParameterSetName = "Time")]
    public int Milliseconds { get; set; }

pass it to

result = new TimeSpan(Days, Hours, Minutes, Seconds, Milliseconds);