Update README.md

Author: svenheden

README.md

@@ -193,7 +193,7 @@ function getParent() {
 ### Body class
 
 When the modal is opened a `ReactModal__Body--open` class is added to the `body` tag.
-You can use this to remove scrolling on the the body while the modal is open.
+You can use this to remove scrolling on the body while the modal is open.
 
 ```CSS
 /* Remove scroll on the body when react-modal is open */