Show errors and warnings on the display (_ERROR, _WARN)

action_raise_error aborts while the macro renders, so an M117 in the same
macro never ran and errors such as the RESUME lane check only reached the
console. messages.cfg adds _ERROR (M117, then raise in a separate macro)
and _WARN (RESPOND TYPE=error + M117); all errors and warnings use them.
PAUSE shows AFC's error as the pause reason; RESUME, CANCEL_PRINT and
PRINT_WARMUP clear the display.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

macros/print/print_start_end.cfg

@@ -26,6 +26,8 @@ gcode:
 
     RESET_FAILURE
 	  CLEAR_PAUSE
+    # Clear what an earlier print or error left on the display
+    M117
 
     _motion_detected
 
@@ -299,7 +301,7 @@ gcode:
             RESTORE_GCODE_STATE NAME=_nozzle_unretract
             SAVE_VARIABLE VARIABLE=nozzle_retract VALUE=0
         {% else %}
-            RESPOND TYPE=error MSG="_NOZZLE_UNRETRACT: extruder too cold, {done} mm still retracted"
+            _WARN MSG="_NOZZLE_UNRETRACT: extruder too cold, {done} mm still retracted"
         {% endif %}
     {% endif %}