update simpletext display inner class for root_group displayio API 9.x

Author: FoamyGuy

adafruit_clue.py

@@ -59,6 +59,7 @@
 import audiopwmio
 import audiocore
 import touchio
+from displayio import CIRCUITPYTHON_TERMINAL
 
 __version__ = "0.0.0+auto.0"
 __repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_CLUE.git"
@@ -150,11 +151,11 @@ def add_text_line(self, color: Union[int, Tuple[int, int, int]] = 0xFFFFFF):
 
     def show(self):
         """Call show() to display the data list."""
-        self._display.show(self.text_group)
+        self._display.root_group = self.text_group
 
     def show_terminal(self):
         """Revert to terminalio screen."""
-        self._display.show(None)
+        self._display.root_group = CIRCUITPYTHON_TERMINAL
 
 
 class Clue:  # pylint: disable=too-many-instance-attributes, too-many-public-methods