Clean up filament change menu (#17702)

Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>

Marlin/src/lcd/menu/menu_filament.cpp

 //
 // Change Filament > Change/Unload/Load Filament
 //
-static PauseMode _change_filament_temp_mode; // =PAUSE_MODE_PAUSE_PRINT
-static int8_t _change_filament_temp_extruder; // =0
+static PauseMode _change_filament_mode; // = PAUSE_MODE_PAUSE_PRINT
+static int8_t _change_filament_extruder; // = 0
 
-inline PGM_P _change_filament_temp_command() {
-  switch (_change_filament_temp_mode) {
-    case PAUSE_MODE_LOAD_FILAMENT:
-      return PSTR("M701 T%d");
-    case PAUSE_MODE_UNLOAD_FILAMENT:
-      return _change_filament_temp_extruder >= 0 ? PSTR("M702 T%d") : PSTR("M702 ;%d");
+inline PGM_P _change_filament_command() {
+  switch (_change_filament_mode) {
+    case PAUSE_MODE_LOAD_FILAMENT:    return PSTR("M701 T%d");
+    case PAUSE_MODE_UNLOAD_FILAMENT:  return _change_filament_extruder >= 0
+                                           ? PSTR("M702 T%d") : PSTR("M702 ;%d");
     case PAUSE_MODE_CHANGE_FILAMENT:
     case PAUSE_MODE_PAUSE_PRINT:
-    default:
-      return PSTR("M600 B0 T%d");
+    default: break;
   }
-  return GET_TEXT(MSG_FILAMENTCHANGE);
+  return PSTR("M600 B0 T%d");
 }
 
 // Initiate Filament Load/Unload/Change at the specified temperature
-static void _change_filament_temp(const uint16_t temperature) {
+static void _change_filament(const uint16_t celsius) {
   char cmd[11];
-  sprintf_P(cmd, _change_filament_temp_command(), _change_filament_temp_extruder);
-  thermalManager.setTargetHotend(temperature, _change_filament_temp_extruder);
+  sprintf_P(cmd, _change_filament_command(), _change_filament_extruder);
+  thermalManager.setTargetHotend(celsius, _change_filament_extruder);
   queue.inject(cmd);
 }
 
 
 inline PGM_P change_filament_header(const PauseMode mode) {
   switch (mode) {
-    case PAUSE_MODE_LOAD_FILAMENT:
-      return GET_TEXT(MSG_FILAMENTLOAD);
-    case PAUSE_MODE_UNLOAD_FILAMENT:
-      return GET_TEXT(MSG_FILAMENTUNLOAD);
+    case PAUSE_MODE_LOAD_FILAMENT:   return GET_TEXT(MSG_FILAMENTLOAD);
+    case PAUSE_MODE_UNLOAD_FILAMENT: return GET_TEXT(MSG_FILAMENTUNLOAD);
     default: break;
   }
   return GET_TEXT(MSG_FILAMENTCHANGE);
 }
 
 void _menu_temp_filament_op(const PauseMode mode, const int8_t extruder) {
-  _change_filament_temp_mode = mode;
-  _change_filament_temp_extruder = extruder;
+  _change_filament_mode = mode;
+  _change_filament_extruder = extruder;
   START_MENU();
   if (LCD_HEIGHT >= 4) STATIC_ITEM_P(change_filament_header(mode), SS_CENTER|SS_INVERT);
   BACK_ITEM(MSG_BACK);
-  ACTION_ITEM(MSG_PREHEAT_1, []{ _change_filament_temp(ui.preheat_hotend_temp[0]); });
-  ACTION_ITEM(MSG_PREHEAT_2, []{ _change_filament_temp(ui.preheat_hotend_temp[1]); });
-  EDIT_ITEM_FAST(int3, MSG_PREHEAT_CUSTOM, &thermalManager.temp_hotend[_change_filament_temp_extruder].target, EXTRUDE_MINTEMP, heater_maxtemp[extruder] - 15, []{
-    _change_filament_temp(thermalManager.temp_hotend[_change_filament_temp_extruder].target);
+  ACTION_ITEM(MSG_PREHEAT_1, []{ _change_filament(ui.preheat_hotend_temp[0]); });
+  ACTION_ITEM(MSG_PREHEAT_2, []{ _change_filament(ui.preheat_hotend_temp[1]); });
+  EDIT_ITEM_FAST(int3, MSG_PREHEAT_CUSTOM, &thermalManager.temp_hotend[_change_filament_extruder].target, EXTRUDE_MINTEMP, heater_maxtemp[extruder] - 15, []{
+    _change_filament(thermalManager.temp_hotend[_change_filament_extruder].target);
   });
   END_MENU();
 }