avoid regressions for linting improvements

@simoncropp thank you for all the linting and other improvements pull requests (for other readers #1365 through #1398)

I'd like to make sure we don't introduce regressions on those improvements in the future. Hence this issue.

I think we should be able to get all those checked on every PR with:

• editor config with a well configured csharp section
• dotnet format --verify-no-changes
• editing one of the existing GHA workflows to run this command.

Thoughts? Is this something you'd be willing to submit a PR for once the linting PRs are merged?

まず既存の GitHub Actions ワークフローとリポジトリのエディター設定を確認し、その後ローカルで dotnet format --verify-no-changes を実行します。関連する editorconfig の C# 設定とフォーマット検証の実行が、リグレッションなしにすべての pull request で正常に成功すれば完了です。