Miscellaneous LCD code renaming, reordering (#12430)

* Move special characters to language.h
* Apply some naming standards
* Clean up menu item draw functions
* Rename some Temperature methods
* UI => ExtUI

Marlin/src/feature/runout.h

@@ -95,7 +95,7 @@ class TFilamentMonitor : public FilamentMonitorBase {
         if (ran_out) {
           filament_ran_out = true;
           #if ENABLED(EXTENSIBLE_UI)
-            UI::onFilamentRunout();
+            ExtUI::onFilamentRunout();
           #endif
           enqueue_and_echo_commands_P(PSTR(FILAMENT_RUNOUT_SCRIPT));
           planner.synchronize();