Consider alternate structure

[MichaelCurrin]

Instead of nesting, look at 3 levels

W3 schools has HTML, JS and others at the top of the page. Or under More on mobile view.

Then the side view has headings and subheadings. Rather than indenting points, the headings are just bigger.
This approach can work for me - however the sidebar can become very long with many items and subitems. That's where accordions comes in or Docsify style of only show subitems when you are on that area.

[MichaelCurrin]

Still, the sidebar would need to pop up from a trigger as it would fill too much of the screen.
So one advanced of nested approach is no sidebar is needed. It just might be harder to go down a few levels or scan across categories to see content.

Maybe there's a balance I see do. On my current cheatsheets top level view I can have accordion to show items under Go, Python etc.

And bring in tags for cross language areas like regex.