Sticky sidebar, like in original terminal.css? #140
Description
Describe the problem you'd like to have solved
The sidebar in the original terminal.css is sticky. Meaning when we scroll down the page, the sidebar hits the top of the browser window and moves with us as we scroll.
Is this functionality already included in mkdocs-terminal as a theme feature and I'm overlooking it?
I could have a look at implementing this if not.