make code refs work

src/plugins/xtriggers/index.rst

@@ -66,4 +66,4 @@ These xtriggers can be registered in the package's ``setup.cfg`` or
 
    It is recommended to implement only one xtrigger per module. This allows
    you to write a ``validate`` function for each xtrigger - see
-   :ref:`xrandom.validate` for an example.
+   :py:mod:`cylc.flow.xtriggers.xrandom` for an example.

src/user-guide/writing-workflows/external-triggers.rst

@@ -288,15 +288,22 @@ properties:
 - The module containing the xtrigger function may also contain a ``validate``
   function taking a single argument, which is a dictionary of all the arguments
   passed to the xtrigger function in ``flow.cylc``. It should raise an
-  exception if validation fails. See :py:mod:`cylc.flow.xtriggers.xrandom` for an example
-  of a validate function.
+  exception if validation fails. See
+  :py:mod:`cylc.flow.xtriggers.xrandom`
+  for an example of a validate function.
+- The arguments you call the xtrigger function with are automatically
+  validated against the function signature, so you don't necessarily need
+  to check for the presence of arguments or their types in the validate
+  function. However, you may want to check that the values are of the correct
+  type or within a certain range.
 
 .. note::
 
    Trigger functions cannot store data Pythonically between invocations
    because each call is executed in an independent process in the process
    pool. If necessary the filesystem can be used for this purpose.
 
+
 .. spelling:word-list::
 
    vv
@@ -383,7 +390,7 @@ time (useful for testing the effect of a long-running trigger function
 - which should be avoided) and has a configurable random chance of
 success. The function signature is:
 
-.. autofunction:: cylc.flow.xtriggers.xrandom.xrandom
+.. automodule:: cylc.flow.xtriggers.xrandom
 
 The ``percent`` argument sets the odds of success in any given call;
 ``secs`` is the number of seconds to sleep before returning; and the
@@ -397,29 +404,6 @@ An example xrandom trigger workflow:
 .. literalinclude:: ../../workflows/xtrigger/xrandom/flow.cylc
    :language: cylc
 
-.. _xrandom.validate:
-
-Validation example using xrandom
-""""""""""""""""""""""""""""""""
-
-The ``xrandom`` xtrigger module contains an example of an xtrigger validation
-function.
-
-Validation functions are run on the inputs to the xtrigger when calling
-``cylc validate``, and should raise an exception with user facing error
-messages if validation fails.
-
-.. autofunction:: cylc.flow.xtriggers.xrandom.validate
-
-.. tip::
-
-   The arguments you call the xtrigger function with are automatically
-   validated against the function signature, so you don't necessarily need
-   to check for the presence of arguments or their types in the validate
-   function. However, you may want to check that the values are of the correct
-   type or within a certain range.
-
-
 .. _Current Trigger Function Limitations:
 
 Current Limitations