The documentation is all in asciidoc.
The documentation is built with
./gradlew :docs:asciidoctor
You will then find the result in docs/build/asciidoc/user.
To get live reload while editing the documentation, you need two shells.
In the first one, do a continuous buid of the documentation.
./gradlew -t :docs:asciidoctor
In the second launch the live reload.
./gradlew -t :docs:livereload
The local port will be printed on the console. The usual URL is http://localhost:35729.