Improve Sidebar in Gatsby-tutorial documentation

[tulikavijay]

Description

Upon clicking on any particular sidebar links in the GatsbyJs Tutorials, the whole section (tutorial section) gets highlighted and listed.

Expected

Only the selected link should be highlighted or focused.

[fk]

Thanks for filing this @tulikavijay—I kept forgetting to do so for at least a week now! 😅

[tulikavijay]

Great! i would like to work on this, any guidance is appreciated!

[fk]

I'd love to provide guidance, but I don't know what's happening there at all.
This worked just fine a few weeks ago, no clue what changed. ¯\_(ツ)_/¯

Even more confusing is that building "www" locally things just work fine:

[fk]

OK, also seeing the issue in my local build (and with gatsby develop, too) after a fresh install of the dependencies.