Update README.md (#867)

* Update README.md

Adding clarification for usage of <Range /> by setting the property in <Slider />

* Update README.md

---------

Co-authored-by: Amumu <[email protected]>

Author: code2be

README.md

@@ -33,14 +33,28 @@ Online examples: https://slider.react-component.now.sh/
 
 ## Usage
 
+## Slider
 ```js
-import Slider, { Range } from 'rc-slider';
+import Slider from 'rc-slider';
 import 'rc-slider/assets/index.css';
 
 export default () => (
   <>
     <Slider />
-    <Range />
+  </>
+);
+```
+
+## Range
+Please refer to [#825](https://github.com/react-component/slider/issues/825) for information regarding usage of `Range`.
+An example:
+```js
+import Slider, { Range } from 'rc-slider';
+import 'rc-slider/assets/index.css';
+
+export default () => (
+  <>
+    <Slider range />
   </>
 );
 ```