Merge branch 'bugfix/fix_build_err_in_cpp_backport_v4.0' into 'release/v4.0'

ble_hid_device_demo: fix build if building with c++ backport v4.0

See merge request espressif/esp-idf!9233

examples/bluetooth/bluedroid/ble/ble_hid_device_demo/main/hid_dev.h

@@ -253,5 +253,9 @@ void hid_keyboard_build_report(uint8_t *buffer, keyboard_cmd_t cmd);
 
 void hid_mouse_build_report(uint8_t *buffer, mouse_cmd_t cmd);
 
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
 #endif /* HID_DEV_H__ */