Hello,

In Airflow 2, we've moved some configuration options to the new section. We also changed the names of some of the configuration options. This is confusing for users who are familiar with the old option and section names.  It would be great if we could add information to the documentation that points to the new name of the options.

https://github.com/apache/airflow/blob/8f48f12128e0d985c6de2603902524859fecbca8/airflow/configuration.py#L139-L169

> 'The {old} option in [{section}] has been renamed to {new}
> 'The {old_key} option in [{old_section}] has been moved to the {new_key} option in '
> '[{new_section}]

Best regards,
Kamil Breguła

tests/core/test_configuration.py
cfg_dict = conf.as_dict()
        
        assert cfg_dict['core']['unit_test_mode'] == 'True'
        assert cfg_dict['core']['percent'] == 'with%inside'
        
        assert cfg_dict['testsection']['testkey'] == '< hidden >'
        assert cfg_dict['kubernetes_environment_variables']['AIRFLOW__TESTSECTION__TESTKEY'] == '< hidden >'
    def test_conf_as_dict_source(self):
        
        cfg_dict = conf.as_dict(display_source=True)
        assert cfg_dict['core']['load_examples'][1] == 'airflow.cfg'
        assert cfg_dict['core']['load_default_connections'][1] == 'airflow.cfg'
        assert cfg_dict['testsection']['testkey'] == ('< hidden >', 'env var')
    def test_conf_as_dict_sensitive(self):
        
        cfg_dict = conf.as_dict(display_sensitive=True)
        assert cfg_dict['testsection']['testkey'] == 'testvalue'
        assert cfg_dict['testsection']['testpercent'] == 'with%percent'
        
        cfg_dict = conf.as_dict(display_sensitive=True, display_source=True)
        assert cfg_dict['testsection']['testkey'] == ('testvalue', 'env var')
    @conf_vars({("core", "percent"): "with%%inside"})
    def test_conf_as_dict_raw(self):
        
        cfg_dict = conf.as_dict(raw=True, display_sensitive=True)
        assert cfg_dict['testsection']['testkey'] == 'testvalue'
        
        assert cfg_dict['testsection']['testpercent'] == 'with%%percent'
        assert cfg_dict['core']['percent'] == 'with%%inside'
    def test_conf_as_dict_exclude_env(self):