Move M115 to cpp

Marlin/src/Marlin.cpp

   return false;
 }
 
-#include "gcode/host/M115.h"
-
 #include "gcode/lcd/M117.h"
 
 #include "gcode/host/M118.h"

Marlin/src/gcode/gcode.cpp

 //
 // Placeholders for non-migrated codes
 //
-extern void gcode_M115();
 extern void gcode_M117();
 extern void gcode_M118();
 extern void gcode_M119();
       case 92: M92(); break;      // M92: Set the steps-per-unit for one or more axes
 
       case 114: M114(); break;    // M114: Report current position
-      case 115: // M115: Report capabilities
-        gcode_M115();
-        break;
+
+      case 115: M115(); break;    // M115: Report capabilities
+
       case 117: // M117: Set LCD message text, if possible
         gcode_M117();
         break;

Marlin/src/gcode/host/M115.h → Marlin/src/gcode/host/M115.cpp

  *
  */
 
+#include "../gcode.h"
+#include "../../inc/MarlinConfig.h"
+
 /**
  * M115: Capabilities string
  */
-void gcode_M115() {
+void GcodeSuite::M115() {
   SERIAL_PROTOCOLLNPGM(MSG_M115_REPORT);
 
   #if ENABLED(EXTENDED_CAPABILITIES_REPORT)