Tutorial rendered markdown area does not scroll to top on page change

[gamebox]

When you move from one tutorial page to another, the scroll position stays put. This is more than annoying when going through the tutorial. Looks like the code to fix this was removed (commented out) as part of https://github.com/solidjs/solid-site/commit/3dc2f19e9abadfedcede4ab75af100f757bc8474 which happened over a year ago.

I am happy to put in a PR to fix it if you would like.