Merge pull request #3494 from vlakoff/documentation

[ci skip] Fix Sphinx broken path
diff --git a/user_guide_src/source/installation/upgrade_300.rst b/user_guide_src/source/installation/upgrade_300.rst
index 484e030..73cc473 100644
--- a/user_guide_src/source/installation/upgrade_300.rst
+++ b/user_guide_src/source/installation/upgrade_300.rst
@@ -532,7 +532,7 @@
 =======================
 
 :doc:`Form Helper <../helpers/form_helper>` function :func:`form_prep()`
-is now just an alias for :doc:`common function <common_functions>`
+is now just an alias for :doc:`common function </general/common_functions>`
 :func:`html_escape()`. It is deprecated and will be removed in the future.
 
 Please use :func:`html_escape()` instead.