[Discussion] Remove use of `dialect_of` macro

What was the purpose of the current `Dialect`?
The `dialect_of` macro makes it difficult to modify your code whenever you add support for Dialect.
And besides the identifier support of Dialect, it seems that it can also support query (Expr).

But... if you have other intentions for macros
Since there is a problem, I would like to discuss it with the maintainers.

閱讀目前的 `Dialect` 定義和 `dialect_of` 巨集的實作，重點關注討論中提到的 identifier 和 `Expr` 支援。查看維護者的評論，以確定該巨集預期扮演的角色。要視為完成，需要有已達成共識的設計和範圍，但 issue 中尚未確立這些內容。

由索引模型根據 Issue 內容生成。