title: Show code line numbers in JupyterLab
body: <p>In Jupyter notebook, <code>cntrl</code>+ <code>m</code> <code>L</code> toggles code line numbers in current cell but how to bring the code line numbers in JupyterLab?</p>
  
  <p>Referred a similar issue opened in <a href="https://github.com/jupyterlab/jupyterlab/issues/4125" rel="noreferrer">github</a> </p>