* [Add]Add Xdoctester

* [Fix]fix beta docstring

* [Doctest]change dirichlet docstring

* [Doctest]change gumbel docstring

* [Doctest]change bernoulli docstring

* [Doctest]change categorical docstring

* [Doctest]change ops.py docstring

* [Doctest]change conv docstring

* [Doctest]change distance docstring, test=docs_preview

* [Change]add ref

* [Change]patch xdoctest debug