title: python bokeh div method doesn't seem to wrap
body: <p>bokeh=='2.1.1', Python==3.8.3</p>
  <p>I have a very large text, which i am fetching from callbacks, and i want div.text to get updated based on that. The text is comma separated strings. I had tried using sizing mode, but it doesn't seem to have an effect</p>
  <pre><code>div = Div(sizing_mode=&quot;stretch_height&quot;)
  </code></pre>
  <p>What effect was expected, if it was not auto wrapping functionality. Also, how do i achieve auto wrap functionality.</p>
  <p>There is a thread where it says Div wraps text automatically, which is an effect i desire <a href="https://github.com/bokeh/bokeh/issues/8654" rel="nofollow noreferrer">github closed issue</a>. For my use case, i'd like it to exhibit the default please!</p>