DS402: Clean up docstrings.
DS402: Clean up docstrings.

Follow PEP-257 regarding overall formatting.  Fix typos.

Fix incorrect usage of Sphinx directives (:return: does not take an
inline type as :param: does).  Standardize on :raises: directive.  Fix
wrapping to eliminate Sphinx warnings.

Add missing parameter and return documentation for is_homed().  Move
all property documentation to the getter functions, where Python
expects it and where it is not ignored by Sphinx.  Fix incorrectly
documented return types.

Improve some descriptions that were unclear (to me).

christiansandberg/canopen,christiansandberg/canopen