Numpydoc for backends

doc/api/backend_mixed_api.rst

@@ -0,0 +1,7 @@
+
+:mod:`matplotlib.backends.backend_mixed`
+========================================
+
+.. automodule:: matplotlib.backends.backend_mixed
+   :members:
+   :show-inheritance:

doc/api/index_backend_api.rst

@@ -6,6 +6,7 @@ backends
 
    backend_bases_api.rst
    backend_managers_api.rst
+   backend_mixed_api.rst
    backend_tools_api.rst
    backend_gtkagg_api.rst
    backend_qt4agg_api.rst