title: Plotly -Round hover decimals in charts
body: <p>How do you round numbers for display in a plotly graph?  I included an MRE below.  Essentially I wanted rounded numbers to appear when the user hovers over the bar.</p>
  <pre><code>import plotly.express as px
  import pandas as pd
  df = pd.DataFrame({'num': [1, 2, 3],
                     'sqrt': pd.Series([1, 2, 3]) ** 0.5})
  fig = px.bar(df, x='num', y='sqrt', title='Square root')
  fig.show()
  </code></pre>