Add Prolog syntax highlighting

[laalsaas]

I found this Prolog Syntax definition and added it to bat. It is under MPL, so I added support for generating Acknowledgement for that license. Feel-free to double-check the legal part.

I had a bit of a hard time creating this PR because much of the tooling in this repo relies on the bat-binary in $PATH instead of the locally built one. This was troubling when using my own acknowledgement code, as well as when generating the syntax test. I ended up hard-coding the path of the binary into the scripts (which I didn't submit for obvious reasons). I'm mentioning this in case anyone runs into the same problem.

Fixes #1409

[sharkdp]

Thank you. Can you look into getting the CI tests to pass? (add changelog entry, look into license check)

[laalsaas]

There are 3 Failing tests:

• Changelog entry, I made one but I think it's missing the PR Number, no problem, can add that.
• The conflicting file endings: Prolog and Perl both claim the .pl extension, I guess it's more sane to leave this to Perl. The interesting question is where to change that, should I just update the .sublime-syntax file or also the .tmLanguage file from which it was generated.
• The License Check: I think Ican't resolve that. The Prolog Syntax is under MPL. The MPL explicitly mentions the GPL in its text. Since the Test just greps for GPL, It fails, even though I didn't include any GPL code.

[sharkdp]

The conflicting file endings: Prolog and Perl both claim the .pl extension, I guess it's more sane to leave this to Perl.

Agreed.

The interesting question is where to change that, should I just update the .sublime-syntax file or also the .tmLanguage file from which it was generated.

Editing .sublime-syntax only is fine, thank you!

The License Check: I think Ican't resolve that. The Prolog Syntax is under MPL. The MPL explicitly mentions the GPL in its text. Since the Test just greps for GPL, It fails, even though I didn't include any GPL code.

@Enselic Any idea how we could resolve this?

[Enselic]

Maybe we could try to use cargo deny for license checks. I use it in other projects and it is more sophisticated than our custom solution. Unsure if it supports submodules though.

If that doesn't work, I think we simply have to make our own check more sophisticated.

[laalsaas]

Hey, is there any chance moving this forward? i.e. would it be an option to add this file to the excluded files?

[Enselic]

I think adding a general exception to MPL is a better approach, but since I think this syntax would be the first MPL syntax, I don't want to approve that myself. New licenses in bat needs to be approved by sharkdp in my view.