add query socket io client code example

Example 1: import socket io frontend

<script src="/socket.io/socket.io.js"></script><script>  const socket = io('http://localhost');</script>

Example 2: socket io query

// Client side
const socket = io({
  query: { token: 'cde' }
});

// Server side
io.on('connection', (socket) => {
  let token = socket.handshake.query.token;
  
  // Do something...
});