title: How to add echarts markpoint to chart for show specific events
body: <p>I want to add echarts markpoint to chart for show specific events, as the figure below. I expect that I can add event on specific date. And when user hover event block(D), they can see tooltip about some details.</p>
  
  <p>I tried to use echarts markpoint option to add event block, but I don't know how to get hover event to show tooltip. And I want to add event to specific data, but now I just can set it position by (x, y). Or Is there any way/option to solve my problem? Thank you!</p>
  
  <pre><code>markPoint: {
    symbol: 'rect',
    symbolSize: 15,
    label: {
      formatter: 'D',
    },
    itemStyle: {
      color: 'rgba(70,78,86,.9)',
    },
    data: [
      { x: 70, y: 140 },
    ],
  },
  </code></pre>
  
  <ul>
  <li>actual result </li>
  </ul>
  
  <p><a href="https://i.imgur.com/cE4HObG.png" rel="nofollow noreferrer">https://i.imgur.com/cE4HObG.png</a></p>
  
  <ul>
  <li>expected result</li>
  </ul>
  
  <p><a href="https://i.imgur.com/UR2UBAO.png" rel="nofollow noreferrer">https://i.imgur.com/UR2UBAO.png</a></p>