Fix the comment about the posix_spawn_file_actions_addchdir support state (#5192)

The refactoring in #5160 moved a comment around such that it appeared as if QNX supports this function - it does not. Clarify the situation.

Author: jakepetroules

Diff for: Sources/CoreFoundation/CFPlatform.c

@@ -2287,9 +2287,10 @@ CF_EXPORT int _CFPosixSpawnFileActionsChdir(_CFPosixSpawnFileActionsRef file_act
   // Glibc versions prior to 2.29 don't support posix_spawn_file_actions_addchdir_np, impacting:
   //  - Amazon Linux 2 (EoL mid-2025)
   return ENOSYS;
-  #elif defined(__OpenBSD__)
+  #elif defined(__OpenBSD__) || defined(__QNX__)
   // Currently missing as of:
   //  - OpenBSD 7.5 (April 2024)
+  //  - QNX 8 (December 2023)
   return ENOSYS;
   #elif defined(__GLIBC__) || TARGET_OS_DARWIN || defined(__FreeBSD__) || (defined(__ANDROID__) && __ANDROID_API__ >= 34) || defined(__musl__)
   // Pre-standard posix_spawn_file_actions_addchdir_np version available in:
@@ -2304,7 +2305,6 @@ CF_EXPORT int _CFPosixSpawnFileActionsChdir(_CFPosixSpawnFileActionsRef file_act
   // Standardized posix_spawn_file_actions_addchdir version (POSIX.1-2024, June 2024) available in:
   //  - Solaris 11.4 (August 2018)
   //  - NetBSD 10.0 (March 2024)
-  //  - QNX 8 (December 2023)
   return posix_spawn_file_actions_addchdir((posix_spawn_file_actions_t *)file_actions, path);
   #endif
 }