Make sidenav selection stick

[wajihaparvez]

Describe the bug

When selecting a page in the sidenav that's only visible after scrolling, once the page opens, the sidenav resets back to the top. This means users have to scroll back down to see the section they're in/open the next page in the section. Constant scrolling could get frustrating, especially since all the H1s are expanded.

Expected behavior

When the selected page opens, the sidenav should stick to the selected section. See example from old docs:

Steps to reproduce

No response

Tooling

• docs-builder
• migration tooling
• I'm not sure

[reakaleek]

Will be fixed by #257