Fix Temperature::init bug with HEATER_4_PIN

Marlin/src/module/temperature.cpp

@@ -1149,7 +1149,7 @@ void Temperature::init() {
     OUT_WRITE(HEATER_3_PIN, HEATER_3_INVERTING);
   #endif
   #if HAS_HEATER_4
-    OUT_WRITE(HEATER_3_PIN, HEATER_4_INVERTING);
+    OUT_WRITE(HEATER_4_PIN, HEATER_4_INVERTING);
   #endif
   #if HAS_HEATED_BED
     OUT_WRITE(HEATER_BED_PIN, HEATER_BED_INVERTING);