Reading flow-typed docs

`documentation` works great on my JS code. However, I also want it to index some flow-typed files that are not code but Flow types with JSDoc attached. I get empty output similar to what was described in #1272. Is it possible to get documentation to parse the flow-types?

Here's an example:
https://github.com/NotePlan/plugins/blob/main/flow-typed/Noteplan.js

Still using v12.x because 13 was failing with ERR_UNSUPPORTED_ESM_URL_SCHEME against node@14

Running via CLI
./node_modules/.bin/documentation build flow-typed/Noteplan.js -c docs/documentation.cfg.json -o docs -f html --shallow --document-exported

config:
{
"noPackage": true,
"project-name":"NotePlan API+@helpers shared files",
"project-homepage": "https://help.noteplan.co/article/70-javascript-plugin-api",
"project-version": "1.0.0",
"project-description": "An attempt to help find @helper functions",
"sort-order":"alpha"
}