message: Small tweaks to the future-incompat docs.
diff: @@ -6,19 +6,32 @@ stop building in a future version of rustc. If any warnings are found, a small
  notice is displayed indicating that the warnings were found, and provides
  instructions on how to display a full report.
  +For example, you may see something like this at the end of a build:
  +
  +```text
  +warning: the following packages contain code that will be rejected by a future
  + version of Rust: rental v0.5.5
  +note: to see what the problems were, use the option `--future-incompat-report`,
  + or run `cargo report future-incompatibilities --id 1`
  +```
  +
  A full report can be displayed with the `cargo report future-incompatibilities
  --id ID` command, or by running the build again with
  the `--future-incompat-report` flag. The developer should then update their
  dependencies to a version where the issue is fixed, or work with the
  developers of the dependencies to help resolve the issue.
  -This feature can be configured through a `[future-incompat-report]`
  -section in `.cargo/config`. Currently, the supported options are:
  +## Configuration
  -```
  +This feature can be configured through a [`[future-incompat-report]`][config]
  +section in `.cargo/config.toml`. Currently, the supported options are:
  +
  +```toml
  [future-incompat-report]
  -frequency = FREQUENCY
  +frequency = "always"
  ```
  -The supported values for `FREQUENCY` are `always` and `never`, which control
  +The supported values for the frequency are `"always"` and `"never"`, which control
  whether or not a message is printed out at the end of `cargo build` / `cargo check`.
  +
  +[config]: config.md#future-incompat-report
  