Bump Prettier to 1.16.4

Summary:
@public
This bumps Prettier to v1.16.4
Only format source files were updated.

Reviewed By: mjesun

Differential Revision: D14454893

fbshipit-source-id: 72f9872fe764a79dbf0d9fab9bebb1456b039f2f

RNTester/js/InputAccessoryViewExample.js

@@ -70,7 +70,9 @@ class InputAccessoryViewExample extends React.Component<InputAccessoryProps> {
         <ScrollView style={styles.fill} keyboardDismissMode="interactive">
           {Array(15)
             .fill()
-            .map((_, i) => <Message key={i} />)}
+            .map((_, i) => (
+              <Message key={i} />
+            ))}
         </ScrollView>
         <InputAccessoryView backgroundColor="#fffffff7">
           <TextInputBar />