title: Open URL when clicking on data points in Plotly scatter plots [Python]
body: <p>I am visualizing a UMAP 2D reduction of a Doc2Vec vector space as an interactive scatter plot with Plotly.</p>
  
  <p>Each point corresponds to a document vector. Aside from the hovering behavior (which displays some information about the document), I want to be able to click on the points so that the URL of the document opens in a new window.</p>
  
  <p>Here is my current code for the figure:</p>
  
  <pre class="lang-py prettyprint-override"><code>fig = go.Figure()
  
  for cat in data.Categories.unique():
    if cat != 'OTHER':
      cat_data = data[data['Categories'] == cat]
      fig.add_trace(go.Scattergl(
          x=cat_data["Component 1"],
          y=cat_data["Component 2"],
          name=cat,
          mode="markers",
          opacity=0.8,
          marker=dict(size=5),
          text=['Label: %s&lt;br&gt;Title: %s'%(d,t) for d,t in cat_data.loc[:,['Labels', 'Document Titles']].values],
          hoverinfo="text"
          ))
  
  fig.update_layout(
      title=title,
      font=dict(
          family="Lato",
          size=16,
          color="#000000"),
      hovermode='closest'
      )
  
  fig.write_html("Plotly/2D_[NN-%s]_[MD-%s].html"%(n_neighbors, min_dist))
  </code></pre>
  
  <p>I have no idea where to start, reading through Plotly documentation didn't seem to help.</p>
  
  <p>Many thanks in advance!</p>