removed Panel.to_json from docs

Young Joong Kim · jreback · commit b43617d2a8aa · 2016-03-10T07:48:33.000-05:00
closes #12571 closes #12581
diff --git a/doc/source/api.rst b/doc/source/api.rst
@@ -1215,7 +1215,6 @@ Serialization / IO / Conversion
    Panel.to_pickle
    Panel.to_excel
    Panel.to_hdf
-   Panel.to_json
    Panel.to_sparse
    Panel.to_frame
    Panel.to_xarray
