Add CIRCUITPYTHON_TERMINAL usage description

Author: RetiredWizard

shared-bindings/displayio/Display.c

@@ -426,6 +426,7 @@ MP_PROPERTY_GETTER(displayio_display_bus_obj,
 
 //|     root_group: Group
 //|     """The root group on the display.
+//|     If the root group is set to displayio.CIRCUITPYTHON_TERMINAL, the default CircuitPython terminal will be shown.
 //|     If the root group is set to ``None``, no output will be shown.
 //|     """
 STATIC mp_obj_t displayio_display_obj_get_root_group(mp_obj_t self_in) {

shared-bindings/displayio/EPaperDisplay.c

@@ -384,6 +384,7 @@ MP_PROPERTY_GETTER(displayio_epaperdisplay_bus_obj,
 
 //|     root_group: Group
 //|     """The root group on the epaper display.
+//|     If the root group is set to displayio.CIRCUITPYTHON_TERMINAL, the default CircuitPython terminal will be shown.
 //|     If the root group is set to ``None``, no output will be shown.
 //|     """
 //|

shared-bindings/framebufferio/FramebufferDisplay.c

@@ -324,6 +324,7 @@ MP_DEFINE_CONST_FUN_OBJ_KW(framebufferio_framebufferdisplay_fill_row_obj, 1, fra
 
 //|     root_group: displayio.Group
 //|     """The root group on the display.
+//|     If the root group is set to displayio.CIRCUITPYTHON_TERMINAL, the default CircuitPython terminal will be shown.
 //|     If the root group is set to ``None``, no output will be shown.
 //|     """
 //|