Remove details about chalk and point to Chalk Book instead.

Author: crlf0710

src/SUMMARY.md

@@ -72,24 +72,13 @@
         - [`TypeFolder` and `TypeFoldable`](./ty-fold.md)
         - [Generic arguments](./generic_arguments.md)
     - [Type inference](./type-inference.md)
-    - [Trait solving (old-style)](./traits/resolution.md)
+    - [Trait solving](./traits/resolution.md)
         - [Higher-ranked trait bounds](./traits/hrtb.md)
         - [Caching subtleties](./traits/caching.md)
         - [Specialization](./traits/specialization.md)
-    - [Trait solving (new-style)](./traits/index.md)
-        - [Lowering to logic](./traits/lowering-to-logic.md)
-            - [Goals and clauses](./traits/goals-and-clauses.md)
-            - [Equality and associated types](./traits/associated-types.md)
-            - [Implied bounds](./traits/implied-bounds.md)
-            - [Region constraints](./traits/regions.md)
-            - [The lowering module in rustc](./traits/lowering-module.md)
-            - [Lowering rules](./traits/lowering-rules.md)
-            - [Well-formedness checking](./traits/wf.md)
-        - [Canonical queries](./traits/canonical-queries.md)
-            - [Canonicalization](./traits/canonicalization.md)
-        - [The SLG solver](./traits/slg.md)
-        - [An Overview of Chalk](./traits/chalk-overview.md)
-        - [Bibliography](./traits/bibliography.md)
+        - [Chalk-based trait solving](./traits/chalk.md)
+        - [Region constraints](./traits/regions.md)
+        - [Chalk-oriented lowering module in rustc](./traits/lowering-module.md)
     - [Type checking](./type-checking.md)
         - [Method Lookup](./method-lookup.md)
         - [Variance](./variance.md)