You have the basic instruction to see the doc with Yuidoc here : 

https://github.com/ipython/ipython/blob/master/IPython/frontend/html/notebook/static/js/README.md

and

https://github.com/ipython/ipython/blob/master/IPython/frontend/html/notebook/static/js/textcell.js

Should have good examples on how to write js "docstring" 

I haven't yet fully understand Yuidoc but it has [nice documentation](http://yui.github.com/yuidoc/), so don't take the 
example as a perfect example on how o do things, but at least it works.