阅读有关Intent here的官方文档
Intent基本上允许机器人订阅特定的事件桶。与每个Intent对应的事件在Intent文档的各个属性中进行了说明。
若要解决您的问题，可以将此部分添加到代码中：

# imports
import discord
from discord.ext import commands

# enable all intents by default
# you can refer the documentation and enable the ones
# that you need and disable what you don't need
intents=discord.Intents.all()

# passing the required keyword argument
bot = commands.Bot(command_prefix='/', intents=intents)