tools/nxstyle: allow CPython API identifiers

[raiden00pl]

Summary

CPython exposes mixed-case PyMem_* and PyOS_* names that applications cannot rename.

Impact

fix CI in apache/nuttx-apps#3746

Testing

CI

[github-actions]

MemBrowse Memory Report

No memory changes detected for:

• arduino-mega2560
• esp32-devkitc
• hifive1-revb
• mirtoo
• qemu-armv8a
• qemu-intel64
• rx65n-rsk2mb
• s698pm-dkit
• stm32-nucleo-f103rb

[xiaoxiang781216]

@raiden00pl need this patch merge first to fix ci error:
https://github.com/apache/nuttx/actions/runs/32699693915/job/97348900849?pr=19944

[simbit18]

@xiaoxiang781216, it looks like some recently added PR have broken the jobs.

====================================================================================
Configuration/Tool: qemu-armv8a/nsh_smp
2026-08-24 07:15:37
------------------------------------------------------------------------------------
  Cleaning...
  Configuring...
  Building NuttX...
roundrobin.c: In function 'get_primes_thread':
Error: roundrobin.c:137:19: error: implicit declaration of function 'atomic_fetch_add'; did you mean 'atomic_fetch_add_4'? [-Werror=implicit-function-declaration]
  137 |       g_rr_values[atomic_fetch_add(&g_rr_value_index, 1)] = id;
      |                   ^~~~~~~~~~~~~~~~
      |                   atomic_fetch_add_4
cc1.exe: all warnings being treated as errors

PR #19867

@zhangyu-duck , please check

[zhangyu-duck]

we need this pr merge, please wait for little
apache/nuttx-apps#3733 (review)

@simbit18