DOC: suppress warnings for Panel4D deprecation (#13989)

Author: jorisvandenbossche

doc/source/dsintro.rst

@@ -1042,6 +1042,7 @@ The following creates a Panel5D. A new panel type object must be sliceable into
 Here we slice to a Panel4D.
 
 .. ipython:: python
+    :okwarning:
 
     from pandas.core import panelnd
     Panel5D = panelnd.create_nd_panel_factory(

doc/source/io.rst

@@ -4012,6 +4012,7 @@ number of options, please see the docstring.
    legacy_file_path = os.path.abspath('source/_static/legacy_0.10.h5')
 
 .. ipython:: python
+   :okwarning:
 
    # a legacy store
    legacy_store = HDFStore(legacy_file_path,'r')
@@ -4059,6 +4060,7 @@ Experimental
 HDFStore supports ``Panel4D`` storage.
 
 .. ipython:: python
+   :okwarning:
 
    p4d = Panel4D({ 'l1' : wp })
    p4d
@@ -4073,6 +4075,7 @@ store your data. Pass the ``axes`` keyword with a list of dimensions
 object). This cannot be changed after table creation.
 
 .. ipython:: python
+   :okwarning:
 
    store.append('p4d2', p4d, axes=['labels', 'major_axis', 'minor_axis'])
    store

doc/source/whatsnew/v0.10.0.txt

@@ -383,6 +383,7 @@ Adding experimental support for Panel4D and factory functions to create n-dimens
 :ref:`Docs <dsintro.panel4d>` for NDim. Here is a taste of what to expect.
 
      .. ipython:: python
+        :okwarning:
 
         p4d = Panel4D(randn(2, 2, 5, 4),
               labels=['Label1','Label2'],