Sanity check old serial names

Marlin/Configuration_adv.h

 
   #define DGUS_RX_BUFFER_SIZE 128
   #define DGUS_TX_BUFFER_SIZE 48
-  //#define DGUS_SERIAL_STATS_RX_BUFFER_OVERRUNS  // Fix Rx overrun situation (Currently only for AVR)
+  //#define SERIAL_STATS_RX_BUFFER_OVERRUNS  // Fix Rx overrun situation (Currently only for AVR)
 
   #define DGUS_UPDATE_INTERVAL_MS  500    // (ms) Interval between automatic screen updates
 

Marlin/src/HAL/AVR/MarlinSerial.h

     #if HAS_DGUS_LCD
       static constexpr unsigned int RX_SIZE   = DGUS_RX_BUFFER_SIZE;
       static constexpr unsigned int TX_SIZE   = DGUS_TX_BUFFER_SIZE;
-      static constexpr bool RX_OVERRUNS       = ENABLED(DGUS_SERIAL_STATS_RX_BUFFER_OVERRUNS);
+      static constexpr bool RX_OVERRUNS       = ENABLED(SERIAL_STATS_RX_BUFFER_OVERRUNS);
     #elif EITHER(ANYCUBIC_LCD_I3MEGA, ANYCUBIC_LCD_CHIRON)
       static constexpr unsigned int RX_SIZE   = 64;
       static constexpr unsigned int TX_SIZE   = 128;

Marlin/src/inc/SanityCheck.h

   #error "DGUS_SERIAL_PORT is now LCD_SERIAL_PORT. Please update your configuration."
 #elif defined(DGUS_BAUDRATE)
   #error "DGUS_BAUDRATE is now LCD_BAUDRATE. Please update your configuration."
+#elif defined(DGUS_STATS_RX_BUFFER_OVERRUNS)
+  #error "DGUS_STATS_RX_BUFFER_OVERRUNS is now STATS_RX_BUFFER_OVERRUNS. Please update your configuration."
+#elif defined(DGUS_SERIAL_PORT)
+  #error "DGUS_SERIAL_PORT is now LCD_SERIAL_PORT. Please update your configuration."
+#elif defined(ANYCUBIC_LCD_SERIAL_PORT)
+  #error "ANYCUBIC_LCD_SERIAL_PORT is now LCD_SERIAL_PORT. Please update your configuration."
+#elif defined(INTERNAL_SERIAL_PORT)
+  #error "INTERNAL_SERIAL_PORT is now MMU2_SERIAL_PORT. Please update your configuration."
 #elif defined(X_DUAL_ENDSTOPS_ADJUSTMENT)
   #error "X_DUAL_ENDSTOPS_ADJUSTMENT is now X2_ENDSTOP_ADJUSTMENT. Please update Configuration_adv.h."
 #elif defined(Y_DUAL_ENDSTOPS_ADJUSTMENT)

Marlin/src/lcd/extui/lib/dgus/DGUSDisplay.cpp

 
 void DGUSDisplay::ProcessRx() {
 
-  #if ENABLED(DGUS_SERIAL_STATS_RX_BUFFER_OVERRUNS)
+  #if ENABLED(SERIAL_STATS_RX_BUFFER_OVERRUNS)
     if (!LCD_SERIAL.available() && LCD_SERIAL.buffer_overruns()) {
       // Overrun, but reset the flag only when the buffer is empty
       // We want to extract as many as valid datagrams possible...