If you publish a library with its source code, I think it's completely useless without some kind of documentation.
If these sources are subject to change frequently (because you're giving to the developers community a work under construction), you normally will not have time to prepare documentation and examples.
OK. In this case the only think you can't omit is including in your package unit tests sources.
Here I want to give prominence to coding unit test classes with the same accuracy you write the rest of the code.
Putting particular attention to name and to write high quality code inside test methods, it will produce your initial documentation "automatically".
Of course when you release an advanced beta or production quality code, you'll include a standard library reference (more on this argument in future).