add support for django.conf.settings.SETTING_NAME

test/test-data/check-parse-settings.test

@@ -0,0 +1,31 @@
+[case testParseSettingsFromFile]
+from django.conf import settings
+
+reveal_type(settings.ROOT_DIR)  # E: Revealed type is 'builtins.str'
+reveal_type(settings.OBJ)  # E: Revealed type is 'django.utils.functional.LazyObject'
+reveal_type(settings.NUMBERS)  # E: Revealed type is 'builtins.list[Any]'
+reveal_type(settings.DICT)  # E: Revealed type is 'builtins.dict[Any, Any]'
+
+[file mysettings.py]
+SECRET_KEY = 112233
+ROOT_DIR = '/etc'
+NUMBERS = ['one', 'two']
+DICT = {}
+
+from django.utils.functional import LazyObject
+OBJ = LazyObject()
+
+[env DJANGO_SETTINGS_MODULE=mysettings]
+[out]
+
+[case testSettingIsInitializedToNone]
+from django.conf import settings
+
+reveal_type(settings.NONE_SETTING)  # E: Revealed type is 'builtins.object'
+
+[file mysettings_not_none.py]
+SECRET_KEY = 112233
+NONE_SETTING = None
+
+[env DJANGO_SETTINGS_MODULE=mysettings_not_none]
+[out]