[Backport release_3.34] fix: Use correct URL for translation process (#…

…9241)

Fixes #9234

Co-authored-by: Harrissou Sant-anna <delazj@gmail.com>

conf.py

@@ -238,7 +238,7 @@ def calculate_tx_slug(filepath):
     .. only:: html and i18n
 
       .. important::
-        Translation is a community effort `you can join <https://qgis.org/en/site/getinvolved/translate.html#becoming-a-translator>`_.
+        Translation is a community effort :ref:`you can join <translation_guidelines>`.
         This page is currently translated at |translation progress|.
     """