🐛 ExtUI F() followups

Followup to 12b5d997a2

Marlin/src/lcd/extui/anycubic_chiron/chiron_tft.cpp

   setSoftEndstopState(true); // enable endstops
 }
 
-void ChironTFT::SendtoTFT(FSTR_P const fstr) {  // A helper to print PROGMEM string to the panel
+void ChironTFT::SendtoTFT(FSTR_P const fstr/*=nullptr*/) {  // A helper to print PROGMEM string to the panel
   #if ACDEBUG(AC_SOME)
     SERIAL_ECHOF(fstr);
   #endif
   while (const char c = pgm_read_byte(str++)) TFTSer.write(c);
 }
 
-void ChironTFT::SendtoTFTLN(FSTR_P const fstr) {
+void ChironTFT::SendtoTFTLN(FSTR_P const fstr/*=nullptr*/) {
   if (fstr) {
     #if ACDEBUG(AC_SOME)
       SERIAL_ECHOPGM("> ");

Marlin/src/lcd/extui/anycubic_chiron/chiron_tft.h

     static void StatusChange(const char * const);
     static void PowerLossRecovery();
     static void PrintComplete();
-    static void SendtoTFT(FSTR_P const);
-    static void SendtoTFTLN(FSTR_P const);
+    static void SendtoTFT(FSTR_P const=nullptr);
+    static void SendtoTFTLN(FSTR_P const=nullptr);
   private:
     static void DetectPanelType();
     static bool ReadTFTCommand();

Marlin/src/lcd/extui/nextion/nextion_tft.cpp

   SEND_VALasTXT("tmppage.M117", msg);
 }
 
-void NextionTFT::SendtoTFT(FSTR_P fstr) { // A helper to print PROGMEM string to the panel
+void NextionTFT::SendtoTFT(FSTR_P const fstr/*=nullptr*/) { // A helper to print PROGMEM string to the panel
   #if NEXDEBUG(N_SOME)
     DEBUG_ECHOF(fstr);
   #endif

Marlin/src/lcd/extui/nextion/nextion_tft.h

     NextionTFT();
     static void Startup();
     static void IdleLoop();
-    static void PrinterKilled(PGM_P, PGM_P);
+    static void PrinterKilled(FSTR_P const, FSTR_P const);
     static void ConfirmationRequest(const char * const);
     static void StatusChange(const char * const);
-    static void SendtoTFT(FSTR_P const);
+    static void SendtoTFT(FSTR_P const=nullptr);
+    //static void SendtoTFTLN(FSTR_P const=nullptr);
     static void UpdateOnChange();
     static void PrintFinished();
     static void PanelInfo(uint8_t);