fix broken empy link

Author: oliver-sanders

src/hyperlinks.rst.include

@@ -9,7 +9,7 @@
 .. _Cylc Discourse Forum (7-to-8 topic): https://cylc.discourse.group/c/cylc/7-to-8/13
 .. _DataPoint: https://www.metoffice.gov.uk/services/data/datapoint
 .. _Discourse: https://cylc.discourse.group/
-.. _EmPy: http://www.alcyone.com/software/empy/
+.. _EmPy: https://pypi.org/project/empy/
 .. _FCM User Guide: http://metomi.github.io/fcm/doc/user_guide/
 .. _FCM: https://metomi.github.io/fcm/doc/
 .. _INI: https://en.wikipedia.org/wiki/INI_file

src/user-guide/writing-workflows/empy.rst

@@ -7,9 +7,8 @@ Cylc also supports the EmPy template processor in workflow configurations.
 Like :ref:`User Guide Jinja2`, EmPy provides variables, mathematical
 expressions, loop control structures, conditional logic, etc., that gets
 expanded to generate the final workflow configuration seen - which must must be
-valid Cylc syntax. See `EmPy documentation
-<http://www.alcyone.com/software/empy>`_ for details of its templating features
-and how to use them.
+valid Cylc syntax. See `EmPy`_ documentation
+for details of its templating features and how to use them.
 
 .. note::