fix: lint

Author: Koooooo-7

docs/helpers.md

@@ -95,6 +95,7 @@ You will get `<a href="/demo/">link</a>`html. Do not worry, you can still set th
 ![logo](https://docsify.js.org/_media/icon.svg ':class=someCssClass')
 
 <!-- Multiple class names -->
+
 ![logo](https://docsify.js.org/_media/icon.svg ':class=someCssClass :class=anotherCssClass')
 ```