Docs website navigation improvements

[jimkring]

Hello everyone. I'm just dipping my toe into the Sycamore waters. I have some feedback about the Docs -> https://sycamore-rs.netlify.app/docs/getting_started/hello_world

The docs site is great! However, when I'm navigating it, there are a couple pain points:

Docs website should (A) highlight current page in navbar and (B) provide next/previous links at bottom and top of page.

• A. In the left navigation area, there's no indication of which page I'm actually on. I would expect the activate page to be highlighted in some way to indicate I'm on that page/heading/etc. Add underline and bold for navigation improvements #660

• B. There's no [<-Back] [Next->] buttons at the top or bottom of the pages to help me progress to the next page.

Note: I can probably live without either of these things, now that I've figured out how the navigation works, but it was quite confusion as a new user who had never been on the page before.

Here's a screenshot with more info. Thanks again!