Embroider's split-at-routes option causes all docfy pages to not get built

[NullVoxPopuli]

Reproduction here: https://github.com/NullVoxPopuli/ember-cheat-sheet Just uncomment this: https://github.com/NullVoxPopuli/ember-cheat-sheet/blob/main/ember-cli-build.js#L23 and run ember s You'll notice that the app's content is now totally gone.