message: Add toolstate to infrastructure list.
diff: @@ -101,4 +101,11 @@ all crates on [crates.io]. Issues may be filed on the [docs.rs
  repository](https://github.com/rust-lang/docs.rs). See the #docs-rs channel on
  Discord for discussion or urgent issues.
  +## Toolstate
  +
  +The state of tools included with Rust are tracked on the [toolstate
  +page](https://rust-lang-nursery.github.io/rust-toolstate/). When each PR is
  +merged via CI, the status of each tool is recorded in a JSON file and stored
  +in the [toolstate repo](https://github.com/rust-lang-nursery/rust-toolstate).
  +
  [crates.io]: https://crates.io/
  