General Issues with formatting result

Hi @Ekrekr, I've been following your work in [dataform](https://github.com/dataform-co/dataform), and I was pleasantly surprised to see that this repository existed, as we wanted to understand how formatting works in the BQ UI.

I want to build a VSCode extension and tooling based on this, to standardize SQL formatting and have the same format between `dataform`, `BQ UI` and `Airflow` SQL.

The best formatter currently which is also compatible with jinja is SQLfluff, and produces very good results once configured.

One of our main problems with the current way formatting works is that the result for complex queries is completely unreadable for a human. Ideally the formatter would format based on some standards such as:
- https://www.sqlstyle.guide/
- https://handbook.gitlab.com/handbook/business-technology/data-team/platform/sql-style-guide/

I would be in general interested in forking this and start hacking on it a bit whenever I have time, and/or provide some examples of how the output can be made more readable.

Lastly, I have a general question: would a change/suggestion in here be applied to the Monaco Editor under the BQ UI?

Thank you for taking your time to read this, and sorry for the long wall of text

まず、リポジトリの現在のフォーマット動作を確認し、複雑なクエリの出力を、Issue にリンクされている SQL Style Guide および GitLab SQL style guide と比較します。SQLFluff formatter と報告者が提示している例を比較の基準として使用し、そのうえで、ここでの変更が BigQuery UI の Monaco Editor に影響するかどうかを確認します。

索引モデルが issue の本文から書いたものです。