title: Seaborn: title and subtitle placement
body: <p>H all,</p>
  
  <p>I'd like to create a scatterplot with a title, subtitle, colours corresponding to a specific variable and size corresponding to another variable. I want to display the colour legend but not the size. Here is what I have so far:</p>
  
  <pre><code># imports
  import seaborn as sns
  import matplotlib
  from matplotlib import style
  import matplotlib.pyplot as plt
  
  # parameters
  matplotlib.rcParams['font.family'] = "roboto"
  style.use('fivethirtyeight')
  
  # load data
  iris = sns.load_dataset('iris')
  
  # plot
  ax = sns.relplot(
      'sepal_length',
      'sepal_width',
      hue='species',
      size='petal_width',
      alpha=0.75,
      kind="scatter",
      legend=False,
      data=iris
  )
  
  # make adjustments
  ax.set_axis_labels(x_var='Sepal Length', y_var='Sepal Width')
  plt.text(x=4.7, y=4.7, s='Sepal Length vs Width', fontsize=16, weight='bold')
  plt.text(x=4.7, y=4.6, s='The size of each point corresponds to sepal width', fontsize=8, alpha=0.75)
  plt.show()
  </code></pre>
  
  <p>Output:</p>
  
  <p><a href="https://i.stack.imgur.com/SAnx5.png" rel="noreferrer"><img src="https://i.stack.imgur.com/SAnx5.png" alt="scatterplot"></a></p>
  
  <p>Here are my questions:</p>
  
  <p>1) Is there a better way to set a subtitle? I tried this using <code>ax.suptitle("blah", y=1.05)</code> but it ends up sitting outside the scope of the figure. I don't like that I have to set x and y coordinates for my title/subtitle.</p>
  
  <p>2) Is there a way for me to display the colour legend without showing the size legend? I would also like to be able to display this legend below the plot (or outside it). <strong>if you can answer that question, I'll change the title of this post, mark your answer as complete and create another question about the titles and subtitles</strong></p>
  
  <p>Many thanks!</p>