docs: Add link to PDF version of docs in sidebar.

Requires a link of the form: <BASEURL>/<lang>/<ver>/micropython-<port>.pdf

docs/conf.py

@@ -48,6 +48,9 @@ html_context = {
         (ver, url_pattern % (ver, micropy_port))
             for ver in micropy_all_versions
     ],
+    'downloads':[
+        ('PDF', url_pattern % (micropy_version, 'micropython-%s.pdf' % micropy_port)),
+    ],
 }
 
 

docs/templates/versions.html

@@ -17,14 +17,12 @@
         <dd><a href="{{ url }}">{{ slug }}</a></dd>
       {% endfor %}
     </dl>
-    <!--
     <dl>
       <dt>Downloads</dt>
       {% for type, url in downloads %}
         <dd><a href="{{ url }}">{{ type }}</a></dd>
       {% endfor %}
     </dl>
-    -->
     <hr/>
     <dl>
       <dt>External links</dt>