Our docs are written in MkDocs using the Material for MkDocs theme. Once you've installed mkdocs you can preview the docs locally and publish them live, subsequently.
The docs are just Markdown files and in order to see the rendered preview locally (before PRing the repo), do:
$ mkdocs serve
INFO - Building documentation...
INFO - Cleaning site directory
WARNING - A relative path to 'user-docs.md' is included in the 'nav' configuration, which is not found in the documentation files
WARNING - A relative path to 'dev-docs.md' is included in the 'nav' configuration, which is not found in the documentation files
WARNING - A relative path to 'discussions.md' is included in the 'nav' configuration, which is not found in the documentation files
[I 200630 14:56:59 server:296] Serving on http://127.0.0.1:8000
[I 200630 14:56:59 handlers:62] Start watching changes
[I 200630 14:56:59 handlers:64] Start detecting changes
When you're done and have committed the changes, you can publish them using the mkdocs gh-deploy command.