title: How can I add a ToolTip to the AvatarGroup "+x" bubble
body: <p>I was wondering if there is a way to add a ToolTip component to the bubble showing the additional avatars in the Avatar Group component.
  Here is an example of how the component renders:
  (Image from Material UI documentation (<a href="https://material-ui.com/components/avatars/#grouped" rel="nofollow noreferrer">https://material-ui.com/components/avatars/#grouped</a>)</p>
  <p>I want to add a ToolTip to the last bubble displaying the name of the remaining users.</p>
  <p><a href="https://i.stack.imgur.com/q8PCR.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/q8PCR.png" alt="enter image description here" /></a></p>
  <p>I am currently adding a ToolTip to each avatar. This is my code</p>
  <pre><code>&lt;AvatarGroup max={4}&gt;
       {users.people.map((person, index) =&gt; (
            &lt;Tooltip title={person.name} key={index}&gt;
                 &lt;Avatar
                      className={classes.smallAvatar}
                      onClick={e =&gt; {
                           handleUserClick(e),
                           handleAvatarClick(person);
                      }}
                      src={person.avatar}
                 &gt;
                      {person.initials}
                 &lt;/Avatar&gt;
            &lt;/Tooltip&gt;
       ))}
  &lt;/AvatarGroup&gt;
  </code></pre>