Replace self.module by my_module (#75196)

While implementing basic Ansible module testing I realised that the `self.module` used in some places is not actually a thing, and I changed to `my_module` to make it work as I understand it was expected.

docs/docsite/rst/dev_guide/testing_units_modules.rst

@@ -369,7 +369,7 @@ Here is a simple mock of :meth:`AnsibleModule.run_command` (taken from :file:`te
         with patch.object(basic.AnsibleModule, 'run_command') as run_command:
             run_command.return_value = 0, '', ''  # successful execution, no output
                 with self.assertRaises(AnsibleExitJson) as result:
-                    self.module.main()
+                    my_module.main()
                 self.assertFalse(result.exception.args[0]['changed'])
         # Check that run_command has been called
         run_command.assert_called_once_with('/usr/bin/command args')
@@ -443,7 +443,7 @@ mock for :meth:`Ansible.get_bin_path`::
         def test_module_fail_when_required_args_missing(self):
             with self.assertRaises(AnsibleFailJson):
                 set_module_args({})
-                self.module.main()
+                my_module.main()
 
 
         def test_ensure_command_called(self):
@@ -508,7 +508,7 @@ This now makes it possible to run tests against the module initiation function::
          })
 
         with self.assertRaises(AnsibleFailJson) as result:
-            self.module.setup_json
+            my_module.setup_json
 
 See also ``test/units/module_utils/aws/test_rds.py``