Add PowerShell completion file

[rashil2000]

No description provided.

[rashil2000]

@Enselic The file extension needs to be .ps1, otherwise PowerShell won't be able to source it.

[Enselic]

@rashil2000 Sorry to mess up the PR, I thought I knew what I was doing, but now CI fails. Any chance you can take over, since you know what needs to be done? My goal was to package the completion file in the tar.gzs and .zips that our CI pipeline build. You can download CI artifacts here to confirm that the file is included and usable: https://github.com/sharkdp/bat/actions/runs/1174961314. (But of course the link is different for each CI run.)

We also build .debs, but I didn't touch those since I don't know the proper path to put it at. It possibly does not make sense to add it there at all.

[rashil2000]

The CI was failing because the file bat.pwsh didn't exist. It's fixed now.

[Enselic]

Thanks! I can confirm that _bat.ps1 is packaged in e.g. bat-v0.18.3-i686-pc-windows-msvc.zip now.

Can you also add an entry about this to CHANGELOG.md as per instructions in https://github.com/sharkdp/bat/blob/master/CONTRIBUTING.md#add-an-entry-to-the-changelog please? Thanks in advance!

(I'm setting Approved already now)

[sharkdp]

Thank you

[Hrxn]

Maybe it should also be mentioned how to use the PowerShell completion file?
I mean, I don't think that this is immediately obvious..

[rashil2000]

Completion files are usually dot-sourced. For example you can put this line in your $PROFILE:

. /file/path/to/_bat.ps1

[Hrxn]

I'm aware, I was just a bit surprised because this does not seem to be mentioned anywhere on the project site. Although it could arguably be considered part of the install instructions, in my opinion.

For what's it worth, it could also be considered presumed knowledge for a PowerShell user, but still..

Speaking of presumed knowledge, why does the name of that file start with an underscore character (_)?
Is that some sort of new PowerShell convention as well?

[rashil2000]

Is that some sort of new PowerShell convention as well?

It does seem like a convention. I've seen it in many places.