I have the same requirement to generate the docs for custom app.
but it seems make-docs and build-docs are all not work now.
So, how to generate the docs for custom app ?
frappe@e8811978c502:~/frappe-bench$ bench --version
5.16.2
frappe@e8811978c502:~/frappe-bench$ bench make-docs erpnextcn current
Usage: bench [OPTIONS] COMMAND [ARGS]...
Try 'bench --help' for help.
Error: No such command 'make-docs'.
frappe@e8811978c502:~/frappe-bench$ bench build-docs
Usage: bench [OPTIONS] COMMAND [ARGS]...
Try 'bench --help' for help.
Error: No such command 'build-docs'.
frappe@e8811978c502:~/frappe-bench$ bench build-docs --help
Usage: bench [OPTIONS] COMMAND [ARGS]...
Try 'bench --help' for help.
Error: No such command 'build-docs'.
frappe@e8811978c502:~/frappe-bench$ bench write-docs --help
Usage: bench [OPTIONS] COMMAND [ARGS]...
Try 'bench --help' for help.