fix links for check_release links CI job (#260)

Author: RRosio

docs/source/config_overview.rst

@@ -69,7 +69,7 @@ NbClassic front-end client
 
 Notebook extensions
 -------------------
-- `Distributing Jupyter Extensions as Python Packages <https://jupyter-notebook.readthedocs.io/en/stable/examples/Notebook/Distributing%20Jupyter%20Extensions%20as%20Python%20Packages.html#Distributing-Jupyter-Extensions-as-Python-Packages>`_
+- `Distributing Jupyter Extensions as Python Packages <https://jupyter-notebook.readthedocs.io/en/v6.5.4/examples/Notebook/Distributing%20Jupyter%20Extensions%20as%20Python%20Packages.html#Distributing-Jupyter-Extensions-as-Python-Packages>`_
 - `Extending the Notebook <https://jupyter-notebook.readthedocs.io/en/stable/extending/index.html>`_
 
 

docs/source/notebook.rst

@@ -3,7 +3,7 @@
 The Jupyter Notebook
 ====================
 
-* `NbClassic Installation <NbClassicUsage>`_
+* :ref:`NbClassic Installation <NbClassicUsage>`
 * `Starting the Notebook <https://jupyter.readthedocs.io/en/latest/running.html>`_
 
 Introduction