Fixing incorrect null-checks in Input/Output and help handling

[powercode]

Fixing null checks in ConvertPSObjectToMamlModel.

With the current behavior, new lines are added/removed every other run causing constant repository churn.

PR Summary

Ensures that scalar null comparison is performed without type conversion.

PR Context

Updating Markdown files without this PR resulted in a file toggling between this: and this:

A real annoyance because of the constant repository churn or selective reverts.