Remove all deprecated methods / props

src/structures/User.js

@@ -296,10 +296,6 @@ class User {
   // These are here only for documentation purposes - they are implemented by TextBasedChannel
   /* eslint-disable no-empty-function */
   send() {}
-  sendMessage() {}
-  sendEmbed() {}
-  sendFile() {}
-  sendCode() {}
 }
 
 TextBasedChannel.applyToClass(User);