message: fix description on how to use robot_ips parameter
diff: <?xml version="1.0" ?>
  <launch>
  - <!--Be sure to pass the IPs of your pandas like robot_ips:={panda_1/robot_ip: <my_ip_1>, panda_2/robot_ip: <my_ip_2>} -->
  + <!--Be sure to pass the IPs of your pandas like robot_ips:="{panda_1/robot_ip: <my_ip_1>, panda_2/robot_ip: <my_ip_2>}" -->
  <arg name="robot_ips" />
  <arg name="robot_id" default="panda_dual" />
  