globals: Warn on removed options, rather than abort

globals.cfg

@@ -114,7 +114,7 @@ gcode:
                               "virtual_sdcard" :
                                 ("on_error_gcode", "CANCEL_PRINT")
                              } %}
-  {% set custom_error = {
+  {% set warn_removed = {
     "start_extruder_set_target_before_level" :
       "The start_extruder_set_target_before_level option has been removed. "
       "Use the start_extruder_probing_temp option instead to set a fixed "
@@ -202,8 +202,8 @@ gcode:
   # Force overrides to use the original types in _KM_GLOBALS.
   {% for k in options %}
     {% if k not in km %}
-      {% if k in custom_error %}
-        {% set dummy = output.append(custom_error[k]) %}
+      {% if k in warn_removed %}
+        {action_respond_info(warn_removed[k])}
       {% else %}
         {% set dummy = output.append("%s is not valid for _KM_OPTIONS." |
                          format(k)) %}