apply review fixes

Author: chrisjsewell

doc/source/index.rst

@@ -317,14 +317,18 @@ Pygments.
 
 Downloading the code as a script
 --------------------------------
+
 Jupyter Sphinx includes 2 roles that can be used to download the code embedded in a document:
-``:jupyter-download:script:`` (for a raw script file) and ``:jupyter-download:notebook:`` (for
-a Jupyter notebook). For example, to download all the code from this document as a script we
+``:jupyter-download:script:`` (for a raw script file) and ``:jupyter-download:notebook:`` or ``:jupyter-download:nb:`` (for
+a Jupyter notebook). 
+
+These roles are equivalent to the standard sphinx `download role <https://www.sphinx-doc.org/en/master/usage/restructuredtext/roles.html#role-download>`__, **except** the extension of the file should not be given.
+For example, to download all the code from this document as a script we
 would use::
 
-    :jupyter-download:script:`index`
+    :jupyter-download:script:`click to download <index>`
 
-Which produces a link like this: :jupyter-download:script:`index`. The name that the role is
+Which produces a link like this: :jupyter-download:script:`click to download <index>`. The target that the role is
 applied to (``index`` in this case) is the name of the document for which you wish to download
 the code. If a document contains ``jupyter-kernel`` directives with ``:id:`` specified, then
 the name provided to ``:id:`` can be used to get the code for the cells belonging to the

requirements.txt

@@ -1,4 +1,4 @@
-sphinx==1.8.5
+sphinx==2.4.4
 ipywidgets>=7.0.0
 IPython
 nbconvert>=5.4