Changed out-file parameter and updated Out-String koan

[ghost]

PR Summary

Resolves #197

Context

Out-String Koan is changed in its approach as carriage returns are "funny" and potentially confusing when trying to compare Get-Item output in a here string. The idea is if the here string is static, then the user only has to update what is piping into out-string. Since this koan is about out-string this feels appropriate.

Changes

• Changed Out-File parameter from -Path to -FilePath to support Windows PowerShell 5.1 and earlier.
• Changed Out-String koan to not require here-string edits, instead requires updates to what is piped into Out-String.

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.

[vexx32]

Love it! Couple minor things we can improve here, but definitely a step in a much better direction! 😍

[vexx32]

Looks great, thanks!

One very minor whitespace nit and we're good to merge. Thanks so much!

[vexx32]

One final thing, but super tiny.

Looks awesome, thank you! 😄

[vexx32]

Looks good!

Thank you very much! 😄