message: Timings takes an array of strings.
diff: @@ -14,7 +14,7 @@ config file (`.cargo/config.toml`) in the `unstable` table. For example:
  [unstable]
  mtime-on-use = true
  multitarget = true
  -timings = true
  +timings = ["html"]
  ```
  Some unstable features will require you to specify the `cargo-features` key in
  