[ADD] general: add documentation about debug mode

odoo_sh/getting_started/create.rst

@@ -150,7 +150,8 @@ Check your outgoing email servers
 
 There is a default mail server provided with Odoo.sh.
 To use it, there must be no enabled outgoing mail server configured in your database in
-:menuselection:`Settings --> Technical --> Outgoing Mail Servers` (Developer mode must be activated).
+:menuselection:`Settings --> Technical --> Outgoing Mail Servers`
+(:doc:`Developer mode <../../general/developer_mode/activate>` must be activated).
 
 After the import of your database,
 all outgoing email servers are disabled so you use the Odoo.sh email server provided by default.

odoo_sh/getting_started/first_module.rst

@@ -265,11 +265,7 @@ and on your production you would not like your module to be installed automatica
 
 Your module may not appear directly in your apps to install either, you need to update your apps list first:
 
-* activate the developer mode from the Settings,
-
-  .. image:: ./media/firstmodule-test-developermode.png
-    :align: center
-
+* activate the :doc:`Developer mode <../../general/developer_mode/activate>`
 * in the apps menu, click the *Update Apps List* button,
 * in the dialog that appears, click the *Update* button.