Improve Utility of Get-Blank

[vexx32]

PR Summary

This PR allows Get-Blank to effectively replace any command in the pipeline, including those that would be used in the middle of a pipeline, or those with parameters.

Context

This is accomplished by offering dummy parameters for both pipeline and regular input. Regular input is taken with ValueFromRemainingArguments so as to capture both arbitrary named parameters and values, without throwing any errors during binding and allowing the assertion to behave correctly.

This allows syntax like this to frame koans:

Get-ChildItem | ____ -First 2 | Should -HaveCount 2

Changes

• Add two parameters to Get-Blank, one for pipe input, one for input via ValueFromRemainingArguments
• Add comment based help for Get-Blank in case people get curious. It is a public-facing function, after all.

Checklist

• Pull Request has a meaningful title.
• Summarised changes.
• Pull Request is ready to merge & is not WIP.
• Added tests / only testable interactively.
  • Make sure you add a new test if old tests do not effectively test the code changed.
• Added documentation / opened issue to track adding documentation at a later date.

[steviecoaster]

Seems sane to me!