G12 defaults per tool. Event G-code for post-toolchange (#16554)

Marlin/src/module/tool_change.cpp

@@ -1067,6 +1067,10 @@ void tool_change(const uint8_t new_tool, bool no_move/*=false*/) {
       fanmux_switch(active_extruder);
     #endif
 
+    #ifdef EVENT_GCODE_AFTER_TOOLCHANGE
+      gcode.process_subcommands_now_P(EVENT_GCODE_AFTER_TOOLCHANGE);
+    #endif
+
     SERIAL_ECHO_START();
     SERIAL_ECHOLNPAIR(MSG_ACTIVE_EXTRUDER, int(active_extruder));