Left Nav is cumbersome to use

[yjukaku]

Hey @apotonick , thanks for your work on Trailblazer and all of its gems. 👍

I just want to log a note here that the left nav leaves something to be desired when clicking through a gem's pages. For example, when looking up how to use Representable, I find myself clicking through all the links on the left side nav, but because the Representable links aren't visible at the top of the page, it's frustrating to scroll down to find the right link.

My suggestion would be to collapse the links for the gems that you aren't currently looking at, like this:

[apotonick]

I would love that, can you do it? :heart_eyes: