Use core constants for microsoft (#46369)

homeassistant/components/microsoft/tts.py

@@ -6,7 +6,7 @@ from pycsspeechtts import pycsspeechtts
 import voluptuous as vol
 
 from homeassistant.components.tts import CONF_LANG, PLATFORM_SCHEMA, Provider
-from homeassistant.const import CONF_API_KEY, CONF_TYPE, PERCENTAGE
+from homeassistant.const import CONF_API_KEY, CONF_REGION, CONF_TYPE, PERCENTAGE
 import homeassistant.helpers.config_validation as cv
 
 CONF_GENDER = "gender"
@@ -15,8 +15,6 @@ CONF_RATE = "rate"
 CONF_VOLUME = "volume"
 CONF_PITCH = "pitch"
 CONF_CONTOUR = "contour"
-CONF_REGION = "region"
-
 _LOGGER = logging.getLogger(__name__)
 
 SUPPORTED_LANGUAGES = [