Navigation sidebar like Trac wiki

To easily navigate GHC users in wiki, how about adding a sidebar to the GitLab wiki?

You may know that GitLab sidebar feature is here:

• https://docs.gitlab.com/ee/user/project/wiki/#customizing-sidebar

I prepared an example of the sidebar in here. Please look at the right sidebar:

• https://gitlab.haskell.org/takenobu-hs/ghc/wikis/home

how is it?