Defining docstrings for functions, classes and methods

[newpavlov]

As far as I can tell there is currently no way to define documentation for items inside module.

Also classes added with m.add_class::<ClassName>(py) do not show in the module level documentation, i.e. in the help(module_name), while auto-completion on them in Python 3 forks just fine.

[Hywan]

:+1: on this one :-)