Remove details about chalk and point to Chalk Book instead.

[crlf0710]

Now that these contents have been moved to the Chalk Book, this PR remove these contents and point to that instead.

[tshepang]

wow, wasn't aware there's so much chalk doc here

[mark-i-m]

Thanks @crlf0710! This is cleanup that has been on my TODO list for a long time.

I have two concerns:

• I don't know if there is any non-chalk-specific knowledge in these chapters that we should condense and keep in some form
• I don't know if any of the chalk-rustc integration content is still relevant. I understood it to be all out of date. So perhaps we should just mention that there is some experimental effort to do integration and leave it at that?

I would really appreciate some guidance from @rust-lang/wg-traits on this...

[mark-i-m]

I would just remove this subchapter and delete ./traits/region.md

[detrumi]

I don't know if there is any non-chalk-specific knowledge in these chapters that we should condense and keep in some form

Let's see, going over the sections:

• Lowering to logic: This has a nice short introduction which won't change much (since it's based on a blog post, and talks about the general ideas), so the introduction can stay. And the "goals and clauses" subsection seems relevant to rustc too
• Canonical queries: this talks about trait queries in rustc, so this should stay here (and possibly not even add it to the chalk book)
• SLG solver: this talks about chalk internals, so that can go to the chalk book
• chalk overview: this can just be replaced by a link to the chalk book

I don't know if any of the chalk-rustc integration content is still relevant. I understood it to be all out of date. So perhaps we should just mention that there is some experimental effort to do integration and leave it at that?

The WF section states "The new-style WF checking has not been implemented in rustc yet", so I think there isn't much. Mentioning something like that sounds like a good plan.

[crlf0710]

Addressed the comments above. Please review again to see if there's more to be adjusted.

[mark-i-m]

Thanks @crlf0710 ! This looks great :)

I have two minor nits, but after that r=me

[crlf0710]

Wait, https://rust-lang.github.io/chalk/book/ is now 404. Did we have a url change or something?

EDIT: pending on https://rust-lang.zulipchat.com/#narrow/stream/144729-wg-traits/topic/Chalk.20book.20address.20change.2E

[crlf0710]

Comments are addressed, and seems CI passes now.

[mark-i-m]

Thanks again!