add document generation to tox, and trigger automatically at CI (also check links in documentation to avoid having dangling pointers to the internet)
diff --git a/docs/examples.rst b/docs/examples.rst
index c049177..6e477fa 100644
--- a/docs/examples.rst
+++ b/docs/examples.rst
@@ -873,7 +873,7 @@
parse examples
------------
+--------------
The following code will prepare the environment:
.. doctest:: tz
@@ -1274,7 +1274,7 @@
Here is the example mentioned in the
-[http://www.python.org/doc/current/lib/module-time.html time module documentation].
+[https://docs.python.org/3/library/time.html time module documentation].
.. testsetup:: tzstr
@@ -1362,7 +1362,7 @@
the `tzinfo` subtypes should deal with the extra hour that happens
when going back to the standard time. Check
-[http://www.python.org/doc/current/lib/datetime-tzinfo.html tzinfo documentation]
+[https://docs.python.org/3/library/datetime.html#datetime.tzinfo tzinfo documentation]
for more information.