Ant ComponentDocumentation command not working

I followed this document and created a component. now i am at 6th section which asks to generate documentation.
In documentation it says "In the directory appinventor/components, execute "ant ComponentDocumentation" when i try to run that command i get following error "BUILD FAILED
Target "ComponentDocumentation" does not exist in the project "components""

I think there is problem in build.xml file but not sure what is issue?

That document is 3 years old . Not sure if it is supposed to work still.

then do u have any idea how can i generate documentation?

Umm i am not sure but -
Run ant BuildDocs in appinventor/appengine

Note that the BuildDocs step is run as part of a build of the appengine module, so if you're using ant or ant noplay from the top level it will be called. You need to have an appropriate version of ruby and bundler installed on your machine for the BuildDocs target to convert the Markdown documentation into HTML, but the build isn't conditional on this step succeeding on your local machine. If you submit a PR to App Inventor, then the documentation will be built and if there is an issue there the build will fail.