[FIX] tutorials/getting_started: fix typos in example model name

Commit f36c612d13 changed the model name
in Chapter 4 without updating the other occurences.

closes odoo/documentation#5516

X-original-commit: b6f923d111
Signed-off-by: Antoine Vandevenne (anv) <anv@odoo.com>

content/developer/tutorials/getting_started/05_securityintro.rst

@@ -93,7 +93,7 @@ access) and a set of permissions: create, read, write and unlink\ [#unlink]_. Su
 rights are usually defined in a CSV file named
 ``ir.model.access.csv``.
 
-Here is an example for our previous ``test.model``:
+Here is an example for our previous `test_model`:
 
 .. code-block:: text