Disable steppers on M112 (#15065)

And change verbiage to not refer to "Emergency Stop."

Marlin/src/gcode/control/M108_M112_M410.cpp

@@ -38,10 +38,10 @@ void GcodeSuite::M108() {
 }
 
 /**
- * M112: Emergency Stop
+ * M112: Full Shutdown
  */
 void GcodeSuite::M112() {
-  kill();
+  kill(PSTR("M112 Shutdown"), true);
 }
 
 /**