Update UsingAScrollView.md

Summary:
Simple spacing update for consistency.

Super simple PR. I'm just fixing the spacing in the documentation to be consistent with the other docs.
Closes https://github.com/facebook/react-native/pull/12549

Differential Revision: D4608409

Pulled By: hramos

fbshipit-source-id: 9df0e3e0260d292e6788f32a713552c30240da47

docs/UsingAScrollView.md

@@ -18,7 +18,7 @@ import { AppRegistry, ScrollView, Image, Text } from 'react-native'
 
 class IScrolledDownAndWhatHappenedNextShockedMe extends Component {
   render() {
-      return(
+      return (
         <ScrollView>
           <Text style={{fontSize:96}}>Scroll me plz</Text>
           <Image source={require('./img/favicon.png')} />