Activate prettier-plugin-toml for pre-commit hooks

[Horstage]

In the pre-commit hook, the plugin prettier-plugin-toml is installed, but not used.
Plugins must be loaded either via CLI command --plugin or in the configuration file.
As there is a configuration file in this project anyways, I added the plugin there.

For more information, see prettier docs.

Contributor checklist

• Included tests for the changes.
• PR title is short, clear, and ready to be included in the user-facing changelog.

Maintainer checklist

• Verified one of these labels is present: backwards incompatible, feature, enhancement, deprecation, bug, dependency, docs or skip-changelog as they determine changelog listing.
• Assign the PR to an existing or new milestone for the target version (following Semantic Versioning).

[webknjaz]

Honestly, I think that multiline entries are better. Could you reconfigure it with that in mind?

[Horstage]

I think so too. But sadly prettier-plugin-toml is "still in alpha state".
There are no configuration options, nor the possibilty to add an inline ignore...

Maybe we should open up an issue?

[webknjaz]

Maybe so. Otherwise, we could also drop it.

Possible replacements and/or additions to evaluate:

• https://toml-sort.rtfd.io (looks like https://github.com/macisamuele/language-formatters-pre-commit-hooks is a wrapper around it)
• https://kieran-ryan.github.io/pyprojectsort/
• https://pyproject-fmt.rtfd.io

These seem closer to the Python ecosystem, anyway.

[webknjaz]

I wonder if having a trailing comma after the last item here would make the formatter to the right thing and keep the list. Worth checking...

[Horstage]

It does not, but that would be lovely.

[Horstage]

I added a Feature Request in the plugin project.

[Horstage]

I created an issue for ignoring lines.

[Horstage]

I used the workaround described in the issue to at least ignore the one instance, where multiline would be nicer.

[chrysle]

@Horstage Could you rebase and investigate the pre-commit failure?