Interactively highlight table of contents to identify current location

[ghost]

• [ ] Using intersection observer, dynamically highlight the current header based on the page viewing location
• [ ] Improve styling of the table of contents

[ghost]

Consider deprioritizing this task

[ghost]

I am closing this for now. Let's reopen if we realistically expect to get to this task in the near future, or mark it as wishlist task later on.

[agarwal]

I'm re-opening. I hope this isn't too hard as plenty of sites do it. We can however keep it as lower priority in moving it down in our project board.

[ghost]

@tmattio This is the only part of markdown rendering which we have not explored yet.