add UC_OSX_RALT to make unicode use the Right Alt key on OSX

quantum/process_keycode/process_unicode_common.c

@@ -49,6 +49,9 @@ void unicode_input_start (void) {
   case UC_OSX:
     register_code(KC_LALT);
     break;
+  case UC_OSX_RALT:
+    register_code(KC_RALT);
+    break;
   case UC_LNX:
     register_code(KC_LCTL);
     register_code(KC_LSFT);
@@ -78,6 +81,9 @@ void unicode_input_finish (void) {
     case UC_WIN:
       unregister_code(KC_LALT);
       break;
+    case UC_OSX_RALT:
+      unregister_code(KC_RALT);
+      break;
     case UC_LNX:
       register_code(KC_SPC);
       unregister_code(KC_SPC);