Update readme to SCSS to remove semicolon highlight (#1428)

Author: FranDias

README.md

@@ -37,12 +37,12 @@ Install react-vis via npm.
     npm install react-vis --save
 
 Include the built main CSS file in your HTML page or via SASS:
-```sass
+```scss
 @import "~react-vis/dist/style";
 ```
 
 You can also select only the styles you want to use. This helps minimize the size of the outputted CSS. Here's an example of importing only the legends styles:
-```sass
+```scss
 @import "~react-vis/dist/styles/legends";
 ```