post #23406 additions

keyboards/handwired/symmetric70_proto/proton_c/info.json

@@ -1,6 +1,4 @@
 {
     "keyboard_name": "Symmetric70 prototype proton-c",
-    "processor": "STM32F303",
-    "bootloader": "stm32-dfu",
-    "board": "QMK_PROTON_C"
+    "development_board": "proton_c"
 }