title: editing messages with discord.py
body: <p>I'm trying to edit my bots sent messages, but I'm getting an error</p>
  <pre class="lang-py prettyprint-override"><code>@client.command()
  async def edit(ctx):
      message = await ctx.send('testing')
      time.sleep(0.3)
      message.edit(content='v2')
  </code></pre>
  <p>Error:</p>
  <pre><code> RuntimeWarning: coroutine 'Message.edit' was never awaited
    message.edit(content='v2')
  RuntimeWarning: Enable tracemalloc to get the object allocation traceback
  </code></pre>
  <p>And by the way, is there any way of editing a message by simply having the message ID?</p>