Update sentence to make it grammatically correct so as to void confusion (reactjs#188)

Author: goyalmunish

content/docs/state-and-lifecycle.md

@@ -79,7 +79,7 @@ We [mentioned before](/docs/components-and-props.html#functional-and-class-compo
 
 You can convert a functional component like `Clock` to a class in five steps:
 
-1. Create an [ES6 class](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Classes) with the same name that extends `React.Component`.
+1. Create an [ES6 class](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Classes), with the same name, that extends `React.Component`.
 
 2. Add a single empty method to it called `render()`.