Use colon

Author: fatosmorina

content/docs/reference-react.md

@@ -50,7 +50,7 @@ See [Using React without JSX](/docs/react-without-jsx.html) for more information
 
 ### `React.Component`
 
-`React.Component` is the base class for React components when they are defined using [ES6 classes](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Classes).
+`React.Component` is the base class for React components when they are defined using [ES6 classes](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Classes):
 
 ```javascript
 class Greeting extends React.Component {