With SINGLENOZZLE only set temperature for the active tool

Marlin/Marlin_main.cpp

@@ -4362,6 +4362,10 @@ inline void gcode_M104() {
   if (get_target_extruder_from_command(104)) return;
   if (DEBUGGING(DRYRUN)) return;
 
+  #if ENABLED(SINGLENOZZLE)
+    if (target_extruder != active_extruder) return;
+  #endif
+
   if (code_seen('S')) {
     float temp = code_value();
     thermalManager.setTargetHotend(temp, target_extruder);
@@ -4516,6 +4520,10 @@ inline void gcode_M109() {
   if (get_target_extruder_from_command(109)) return;
   if (DEBUGGING(DRYRUN)) return;
 
+  #if ENABLED(SINGLENOZZLE)
+    if (target_extruder != active_extruder) return;
+  #endif
+
   bool no_wait_for_cooling = code_seen('S');
   if (no_wait_for_cooling || code_seen('R')) {
     float temp = code_value();