Update README.md

MoOx · MoOx · commit 4cd54fcc3847 · 2020-01-30T00:03:36.000+01:00
diff --git a/README.md b/README.md
@@ -186,7 +186,7 @@ Notification.t => option(string)
 
 #### `ReactNativePushNotificationIOS.Notification.getContentAvailable`
 
-```re
+```reason
 Notification.t => bool
 ```
 
