Cannot reach bottom of TOC in the docs without scrolling to bottom

[designbyadrian]

It's not possible to see the entire contents of Superpowered Javascript SDK without scrolling to the bottom of the entire page.

Steps to reproduce:

1. Use a screen that's 15" or less
2. Visit https://superpowered.com/js-wasm-sdk/docs.html
3. Move pointer to the sidebar with the headings, try to scroll to bottom.

Expected results:

Sidebar is scrolled, revealing the headings further down

Actual results:

Whole page is scrolled, except the sidebar.

[gaborszanto]

fixed