If tutorial steps is longer than the window height, the list of steps do not scroll #144

https://drive.google.com/file/d/1e8pCoNE6XGXfjiKf3nIruF58TXo7tkR2/view
https://metaljs.com/docs/tutorials/tutorial-todo-jsx/before-we-start.html

When you're looking at a tutorial, the list of steps on the left do not scroll if the window height is smaller than the list. The example that I found was on Tutorials for Metal.js. Not sure if this was already addressed (or necessary), but I shall put this here... Thanks!