docs: "Modal", "Overlay", "Portal", "Transitions" sidebar links are broken

[mattxwang]

On the live docs page, https://react-bootstrap.github.io/react-overlays/modal/, the "Modal", "Overlay", "Portal", "Transitions" sidebar links are broken. They're throwing an internal 404, most likely because the corresponding page isn't routed properly. However, visiting each individual page (e.g. https://react-bootstrap.github.io/react-overlays/overlay/ for the Overlay) works.

I can investigate this over the weekend if a fix isn't already in the works.

[mattxwang]

Hm, so when I clone this locally nothing happens. I think it might have to do with GitHub Pages - a similar problem to the issue brought up here.

(After some testing, I believe it is the issue. Opening new tabs works totally fine for all the sidebar links, it's just the internal router getting confused with the URL)

Not sure exactly how to resolve this, since I don't have much experience with Gatsby (and we can't just make it open in a new tab like last time). I think this drop-in file might be one relevant step.