docs: simple update

Author: Scrum

README.md

@@ -7,11 +7,31 @@
 [![Standard Code Style][style]][style-url]
 [![Chat][chat]][chat-badge]
 
-This plugin add webp supporting in your html.
+This plugin add webp supporting in your html. Also supports [`<amp-img>`](https://amp.dev/documentation/components/amp-img/)
+
+## Install
+```bash
+$ npm i posthtml posthtml-webp
+```
+
+## Usage
+
+``` js
+const fs = require('fs');
+const posthtml = require('posthtml');
+const posthtmlWebp = require('posthtml-webp');
+
+posthtml()
+    .use(posthtmlWebp(/* Plugin options */))
+    .process(html/*, options */)
+    .then(result => fs.writeFileSync('./after.html', result.html));
+```
+## Example 
 
 Before:
 ``` html
 <img src="image.jpg">
+<amp-img alt="photo" width="550" height="368" layout="responsive" src="photo.png"></amp-img>
 ```
 
 After:
@@ -20,47 +40,19 @@ After:
     <source type="image/webp" srcset="image.jpg.webp">
     <img src="image.jpg">
 </picture>
-```
-
-Also supports [`<amp-img>`](https://amp.dev/documentation/components/amp-img/)
-
-Before:
-```html
-<amp-img alt="photo" width="550" height="368" layout="responsive" src="photo.png"></amp-img>
-```
-
-After:
-```html
 <amp-img alt="photo" width="550" height="368" layout="responsive" src="photo.png.webp">
     <amp-img alt="photo" width="550" height="368" layout="responsive" src="photo.png" fallback=""></amp-img>
 </amp-img>
 ```
 
-## Install
-
-> npm i posthtml posthtml-webp
+## Options
 
-## Plugin options
-`replaceExtension` (boolean)
-
-**Default:** false
-
-Replace the extension of the source image with .webp instead of appending .webp to the original filename
-
-**Example**: image.jpg => image.webp (instead of image.jpg.webp)
-
-## Usage
+#### `replaceExtension`
 
-``` js
-const fs = require('fs');
-const posthtml = require('posthtml');
-const posthtmlWebp = require('posthtml-webp');
-
-posthtml()
-    .use(posthtmlWebp(/* Plugin options */))
-    .process(html/*, options */)
-    .then(result => fs.writeFileSync('./after.html', result.html));
-```
+Type: `boolean`  
+Default: `false`  
+Description: *Replace the extension of the source image with .webp instead of appending .webp to the original filename*  
+Example: `image.jpg => image.webp (instead of image.jpg.webp)`
 
 ### License [MIT](LICENSE)