Feature request: allow aligning to a different element from the one that triggers the tooltip

[salomvary]

Thanks for this great library! I have a little feature request..

Given the following code:

  <Tooltip placement="left" overlay={text}>
    <div style={{ background: 'blue', padding: '100px', margin: '100px' }}>
      <div style={{ background: 'white' }}>Target</div>
    </div>
  </Tooltip>

Allow positioning the tooltip to the inner div, instead of the outer one, while still activating it when the mouse enters the outer div.