message: docs: Update Radio README.md
  Added example with default value
diff: @@ -39,6 +39,31 @@ function Example() {
  }
  ```
  +### Default value
  +
  +To set a default value, you can pass the `value` of the current checked radio to the `state` property on `useRadioState`.
  +
  +```jsx
  +import { useRadioState, Radio, RadioGroup } from "reakit/Radio";
  +
  +function Example() {
  + const radio = useRadioState({ state: "orange" });
  + return (
  + <RadioGroup {...radio} aria-label="fruits">
  + <label>
  + <Radio {...radio} value="apple" /> apple
  + </label>
  + <label>
  + <Radio {...radio} value="orange" /> orange
  + </label>
  + <label>
  + <Radio {...radio} value="watermelon" /> watermelon
  + </label>
  + </RadioGroup>
  + );
  +}
  +```
  +
  ## Accessibility
  - `Radio` has role `radio`.
  