Update link to curated transmogrifier training

Author: stevepiercy

docs/backend/upgrading/intro.md

@@ -132,7 +132,7 @@ This approach allows you to migrate from Plone 4 to 6, from Python 2 to 3, and f
 It is recommended for large and complex migrations.
 
 The recommended tool for this is [`collective.exportimport`](https://github.com/collective/collective.exportimport).
-An alternative is `transmogrifier` (see the training {ref}`training:transmogrifier-label`).
+An alternative is `transmogrifier` (see the training {ref}`training-2022:transmogrifier-label`).
 
 
 (introduction-major-changes-label)=

docs/conf.py

@@ -188,6 +188,7 @@
     "plone": ("https://6.docs.plone.org/", None),  # for imported packages
     "python": ("https://docs.python.org/3/", None),
     "training": ("https://training.plone.org/", None),
+    "training-2022": ("https://2022.training.plone.org/", None),
 }