Fix use of "it's" in docs

docs/_posts/2013-07-17-react-v0-4-0.md

@@ -24,7 +24,7 @@ When you're ready, [go download it](/react/downloads.html)!
 * Removed `React.autoBind`. [Read our blog post for details...](http://facebook.github.io/react/blog/2013/07/02/react-v0-4-autobind-by-default.html)
 * Improvements to forms. We've written wrappers around `<input>`, `<textarea>`, `<option>`, and `<select>` in order to standardize many inconsistencies in browser implementations. This includes support for `defaultValue`, and improved implementation of the `onChange` event, and circuit completion. [Read the docs for details...](http://facebook.github.io/react/docs/forms.html)
 * We've implemented an improved synthetic event system that conforms to the W3C spec.
-* Updates to your component are batched now, which may result in a significantly faster re-render of components. `this.setState` now takes an optional callback as it's second parameter. If you were using `onClick={this.setState.bind(this, state)}` previously, you'll want to make sure you add a third parameter so that the event is not treated as the callback.
+* Updates to your component are batched now, which may result in a significantly faster re-render of components. `this.setState` now takes an optional callback as its second parameter. If you were using `onClick={this.setState.bind(this, state)}` previously, you'll want to make sure you add a third parameter so that the event is not treated as the callback.
 
 ### JSX
 

docs/docs/07.1-more-about-refs.md

@@ -39,7 +39,7 @@ Consider the case when you wish to tell an `<input />` element (that exists with
 ```
 
 
-Notice how, in this example, we want to "tell" the input something - something that it cannot infer from it's props over time. In this case we want to "tell" it that it should now become focused. However, there are some challenges. What is returned from `render()`` is not your actual composition of "child" components, it is merely a *description* of the children at a particular instance in time - a snapshot, if you will.
+Notice how, in this example, we want to "tell" the input something - something that it cannot infer from its props over time. In this case we want to "tell" it that it should now become focused. However, there are some challenges. What is returned from `render()`` is not your actual composition of "child" components, it is merely a *description* of the children at a particular instance in time - a snapshot, if you will.
 
 > Note:
 >