docs: Add missing discard hook

Author: marshallswain

docs/api-overview.md

@@ -99,7 +99,7 @@ import feathers from '@feathersjs/feathers'
 import socketio from '@feathersjs/socketio-client'
 import auth from '@feathersjs/authentication-client'
 import io from 'socket.io-client'
-import { iff } from 'feathers-hooks-common'
+import { iff, discard } from 'feathers-hooks-common'
 import feathersVuex from 'feathers-vuex'
 
 const socket = io('http://localhost:3030', {transports: ['websocket']})