text: Title: fix js when right bar does not appear
  Body: there is some JS code that highlights the currently active section in the right sidebar. See this: https://docs.ploomber.io/en/latest/user-guide/cli.html
  
  However, not all sections in the docs show the right sidebar, in such case, the console keeps throwing an error:
  
  ![image](https://user-images.githubusercontent.com/989250/168489626-ffa950a4-3375-4cd4-b890-4b927b118f34.png)
  