Merge pull request #3394 from cody/getDOMNode

Fix in docs: getDOMNode --> findDOMNode

docs/docs/ref-01-top-level-api.md

@@ -137,7 +137,7 @@ Verifies the object is a ReactElement.
 ```javascript
 DOMElement findDOMNode(ReactComponent component)
 ```
-If this component has been mounted into the DOM, this returns the corresponding native browser DOM element. This method is useful for reading values out of the DOM, such as form field values and performing DOM measurements. When `render` returns `null` or `false`, `this.getDOMNode()` returns `null`.
+If this component has been mounted into the DOM, this returns the corresponding native browser DOM element. This method is useful for reading values out of the DOM, such as form field values and performing DOM measurements. When `render` returns `null` or `false`, `findDOMNode` returns `null`.
 
 
 ### React.DOM