While I'm unsure of your project framework but if you already have a Git repository for it, then you could look into creating your documentation using reStructuredText and Sphinx to auto-generate all the static content (HTML, CSS, JS etc)
You can then deploy it via ReadTheDocs which handles building your documentation (via Git web-hook) and hosts it on a publicly accessible URL of your choice.
While it does have a bit of a learning curve but once you get the hang of it, all you'd need to create documentation is a Text Editor and Git commits :)
If you need an example, you can browse the one made by LetsEncrypt
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