Remove legacy keycodes, part 2 (#18660)

* `KC_SYSREQ` -> `KC_SYRQ`

And one `KC_ALT_ERASE` -> `KC_ERAS`

* `KC_NONUS_BSLASH` -> `KC_NUBS`

* `KC_NUMLOCK` -> `KC_NUM`

* `KC_CLCK` -> `KC_CAPS`

* `KC_SCROLLLOCK` -> `KC_SCRL`

* `KC_LBRACKET` -> `KC_LBRC`

* `KC_RBRACKET` -> `KC_RBRC`

* `KC_CAPSLOCK` -> `KC_CAPS`

keyboards/contra/keymaps/maxr1998/keymap.c

@@ -179,7 +179,7 @@ void update_tri_layer_user(void) {
 void led_set_user(uint8_t usb_led) {
   // Force-enable Numlock
   if (!(usb_led & (1<<USB_LED_NUM_LOCK))) {
-    register_code(KC_NUMLOCK);
-    unregister_code(KC_NUMLOCK);
+    register_code(KC_NUM_LOCK);
+    unregister_code(KC_NUM_LOCK);
   }
 }