Added manual and script for PowerShell autocomplete

[kirinnee]

What type of PR is this?

• bug
• cleanup
• documentation
• feature

What this PR does / why we need it:

This adds documentation and script to enable autocomplete on both
PowerShell and PS Core on Windows (and other platforms)

Special notes for your reviewer:

Not sure how to automate testing

Testing

Following instructions added to the manual in a PowerShell environment

[saschagrunert]

LGTM, but I have no knowledge about the PowerShell. :)

[kirinnee]

Any updates? Or anything I need to improve before it can be merged?

[lynncyrin]

LGTM!

[lynncyrin]

Oh, @kirinnee the docs tests are failing b/c you're missing a heading. Check the logs here => https://github.com/urfave/cli/pull/1139/checks?check_run_id=683967954

[lynncyrin]

Echoing my last comment, you'll need to add PowerShell Support to the table of contents! Please do re-request me when you've done that 👍

[kirinnee]

Hi I have updated accordingly. Please lmk if there are more changes needed! Thank you!

[lynncyrin]

🚢

[stale]

This issue or PR has been automatically marked as stale because it has not had recent activity. Please add a comment bumping this if you're still interested in it's resolution! Thanks for your help, please let us know if you need anything else.

[kirinnee]

Any updates?

[stale]

This issue or PR has been bumped and is no longer marked as stale! Feel free to bump it again in the future, if it's still relevant.

[asahasrabuddhe]

LGTM