Cleanup: Prefer React.Element over React$?Element

Reviewed By: vjeux

Differential Revision: D4013049

fbshipit-source-id: 18a447fdbc584418d6a51770363bcd221e7fb7dc

Libraries/Experimental/SwipeableRow/SwipeableQuickActionButton.js

@@ -59,7 +59,7 @@ class SwipeableQuickActionButton extends React.Component {
     textStyle: Text.propTypes.style,
   };
 
-  render(): ?ReactElement<any> {
+  render(): ?React.Element<any> {
     if (!this.props.imageSource && !this.props.text) {
       return null;
     }