[FIX] dev/reference: Fix external reference

The tour utils were red and moved in Odoo (odoo/odoo#107618).

closes #6496

Signed-off-by: Antoine Vandevenne (anv) <anv@odoo.com>

Author: rrahir

content/developer/reference/backend/testing.rst

@@ -597,7 +597,7 @@ Javascript
 #. Add any step you want.
 
 Every step contains at least a trigger. You can either use the `predefined steps
-<{GITHUB_PATH}/addons/web_tour/static/src/js/tour_step_utils.js>`_ or write your own personalized
+<{GITHUB_PATH}/addons/web_tour/static/src/tour_service/tour_utils.js#L426>`_ or write your own personalized
 step.
 
 Here are some example of steps:

locale/sources/developer.pot

@@ -10395,7 +10395,7 @@ msgid "Add any step you want."
 msgstr ""
 
 #: ../../content/developer/reference/backend/testing.rst:599
-msgid "Every step contains at least a trigger. You can either use the `predefined steps <https://github.com/odoo/odoo/blob/saas-16.1/addons/web_tour/static/src/js/tour_step_utils.js>`_ or write your own personalized step."
+msgid "Every step contains at least a trigger. You can either use the `predefined steps <https://github.com/odoo/odoo/blob/saas-16.3/addons/web_tour/static/src/tour_service/tour_utils.js#L426>`_ or write your own personalized step."
 msgstr ""
 
 #: ../../content/developer/reference/backend/testing.rst:603