Use `thiserror` instead of `anyhow`?

[hch12907]

anyhow::Error is an opaque type and dynamically dispatched. It can be useful to present errors as an enum in order for downstream users to see what error has occurred.

[cathay4t]

Personally, I am not fan neither anyhow or thiserror. I intend to impl all traits manually. Currently, this anyhow is making my debug life worse as it only show top level error by default.

In generate, pull request for removing anyhow is welcome. I can remove thiserror later.